Glass

This article is about the material. For other uses, see Glass (disambiguation). Moldavite, a natural glass formed by meteorite impact, from Besednice, Bohemia Roman Cage Cup from the 4th century A.D. Oldest mouth-blown window-glass in Sweden (Kosta Glasbruk, 1742). In the middle is the mark from the glassblower's pipe. Glass is an amorphous (non-crystalline) solid material. Glasses are typically brittle, and often optically transparent. The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, made of about 75% silica (SiO2) plus Na2O, CaO, and several minor additives. Often, the term glass is used in a restricted sense to refer to this specific use. In science, however, the term glass is usually defined in a much wider sense, including every solid that possesses a non-crystalline (i.e. amorphous) structure and that exhibits a glass transition when heated towards the liquid state. In this wider sense, glasses can be made of quite different classes of materials: metallic alloys, ionic melts, aqueous solutions, molecular liquids, and polymers. For many applications (bottles, eyewear) polymer glasses (acrylic glass, polyethylene terephthalate) are a lighter alternative to traditional silica glasses. Glass, as a substance, plays an essential role in science and industry. Their chemical, physical, and in particular optical properties make them suitable for applications such as flat glass, container glass, optics and optoelectronics material, laboratory equipment, thermal insulator (glass wool), reinforcement materials (glass-reinforced plastic, glass fiber reinforced concrete), and glass art (art glass, studio glass). Contents 1 Silicate glass 1.1 History 1.2 Glass ingredients 1.3 Contemporary glass production 1.4 Glassmaking in the laboratory 2 Other glasses 2.1 Network glasses 2.2 Amorphous metals 2.3 Electrolytes 2.4 Aqueous solutions 2.5 Molecular liquids 2.6 Polymers 2.7 Colloidal glasses 2.8 Glass-ceramics 3 Structure 4 Glass versus supercooled liquid 4.1 Behavior of antique glass 5 Physical properties 5.1 Optical properties 5.2 Color 6 Glass art 6.1 Museums 7 See also 8 References 9 Bibliography 10 External links // Silicate glass Silica (the chemical compound SiO2) is a common fundamental constitute of glass. In nature, vitrification of quartz occurs when lightning strikes sand, forming hollow, branching rootlike structures called fulgurite. History Main article: History of glass The history of creating glass can be traced back to 3500 BCE in Mesopotamia.1 The term glass developed in the late Roman Empire. It was in the Roman glassmaking center at Trier, now in modern Germany, that the late-Latin term glesum originated, probably from a Germanic word for a transparent, lustrous substance.2 Glass ingredients Quartz sand (silica) is the main raw material in commercial glass production While fused quartz (primarily composed of SiO2) is used for some special applications, it is not very common due to its high glass transition temperature of over 2300 °C. Normally, other substances are added to simplify processing. One is sodium carbonate (Na2CO3), which lowers the glass transition to about 1500 °C. However, the soda makes the glass water soluble, which is usually undesirable, so lime (calcium oxide (CaO), generally obtained from limestone), some magnesium oxide (MgO) and aluminium oxide (Al2O3) are added to provide for a better chemical durability. The resulting glass contains about 70 to 74% silica by weight and is called a soda-lime glass.3 Soda-lime glasses account for about 90% of manufactured glass. Most common glass has other ingredients added to change its properties. Lead glass or flint glass is more 'brilliant' because the increased refractive index causes noticeably more specular reflection and increased optical dispersion. Adding barium also increases the refractive index. Thorium oxide gives glass a high refractive index and low dispersion and was formerly used in producing high-quality lenses, but due to its radioactivity has been replaced by lanthanum oxide in modern eye glasses.citation needed Iron can be incorporated into to glass to absorb infrared energycitation needed, for example in heat absorbing filters for movie projectors, while cerium(IV) oxide can be used for glass that absorbs UV wavelengths.citation needed Borosilicate glasses (e.g. Pyrex) have as main constituents silica and boron oxide. They have very low coefficients of thermal expansion (7740 Pyrex COE is 32.5 × 10−7 /°C as compared to 8.36 x 10-5/°C for one type of soda-lime glass),4 making them more dimensionally stable. The lower COE also makes them less subject to stress caused by thermal expansion, thus less vulnerable to cracking from thermal shock. They are commonly used for reagent bottles and optical components. Another common glass ingredient is "cullet" (recycled glass). The recycled glass saves on raw materials and energy. However, impurities in the cullet can lead to product and equipment failure. Fining agents such as sodium sulfate, sodium chloride, or antimony oxide may be added to reduce the number of air bubbles in the glass mixture.3 Glass batch calculation is the method by which the correct raw material mixture is determined to achieve the desired glass composition. Contemporary glass production A modern greenhouse in Wisley Garden, England, made from float glass Main articles: Glass production, Float glass, and Glazier Following the glass batch preparation and mixing, the raw materials are transported to the furnace. Soda-lime glass for mass production is melted in gas fired units. Smaller scale furnaces for specialty glasses include electric melters, pot furnaces, and day tanks.3 After melting, homogenization and refining (removal of bubbles), the glass is formed. Flat glass for windows and similar applications is formed by the float glass process, developed between 1953 and 1957 by Sir Alastair Pilkington and Kenneth Bickerstaff of the UK's Pilkington Brothers, who created a continuous ribbon of glass using a molten tin bath on which the molten glass flows unhindered under the influence of gravity. The top surface of the glass is subjected to nitrogen under pressure to obtain a polished finish.5 Container glass for common bottles and jars is formed by blowing and pressing methods. Further glass forming techniques are summarized in the table Glass forming techniques. Once the desired form is obtained, glass is usually annealed for the removal of stresses. Surface treatments, coatings or lamination may follow to improve the chemical durability (glass container coatings, glass container internal treatment), strength (toughened glass, bulletproof glass, windshields), or optical properties (insulated glazing, anti-reflective coating). Glassmaking in the laboratory A vitrification experiment for the study of nuclear waste disposal at Pacific Northwest National Laboratory. New chemical glass compositions or new treatment techniques can be initially investigated in small-scale laboratory experiments. The raw materials for laboratory-scale glass melts are often different from those used in mass production because the cost factor has a low priority. In the laboratory mostly pure chemicals are used. Care must be taken that the raw materials have not reacted with moisture or other chemicals in the environment (such as alkali oxides and hydroxides, alkaline earth oxides and hydroxides, or boron oxide), or that the impurities are quantified (loss on ignition).6 Evaporation losses during glass melting should be considered during the selection of the raw materials, e.g., sodium selenite may be preferred over easily evaporating SeO2. Also, more readily reacting raw materials may be preferred over relatively inert ones, such as Al(OH)3 over Al2O3. Usually, the melts are carried out in platinum crucibles to reduce contamination from the crucible material. Glass homogeneity is achieved by homogenizing the raw materials mixture (glass batch), by stirring the melt, and by crushing and re-melting the first melt. The obtained glass is usually annealed to prevent breakage during processing.67 In order to make glass from materials with poor glass forming tendencies, novel techniques are used to increase cooling rate, or reduce crystal nucleation triggers. Examples of these techniques include aerodynamic levitation (cooling the melt whilst it floats on a gas stream), splat quenching (pressing the melt between two metal anvils) and roller quenching (pouring the melt through rollers). See also: Optical lens design, Fabrication and testing of optical components Other glasses Network glasses A CD-RW (CD). Chalcogenide glasses form the basis of re-writable CD and DVD solid-state memory technology.8 Some glasses that do not include silica as a major constituent may have physico-chemical properties useful for their application in fibre optics and other specialized technical applications. These include fluoride glasses, aluminosilicates, phosphate glasses, borate glasses, and chalcogenide glasses. There are three classes of components for oxide glasses: network formers, intermediates, and modifiers. The network formers (silicon, boron, germanium) form a highly cross-linked network of chemical bonds. The intermediates (titanium, aluminium, zirconium, beryllium, magnesium, zinc) can act as both network formers and modifiers, according to the glass composition. The modifiers (calcium, lead, lithium, sodium, potassium) alter the network structure; they are usually present as ions, compensated by nearby non-bridging oxygen atoms, bound by one covalent bond to the glass network and holding one negative charge to compensate for the positive ion nearby. Some elements can play multiple roles; e.g. lead can act both as a network former (Pb4+ replacing Si4+), or as a modifier. The presence of non-bridging oxygens lowers the relative number of strong bonds in the material and disrupts the network, decreasing the viscosity of the melt and lowering the melting temperature. The alkaline metal ions are small and mobile; their presence in glass allows a degree of electrical conductivity, especially in molten state or at high temperature. Their mobility however decreases the chemical resistance of the glass, allowing leaching by water and facilitating corrosion. Alkaline earth ions, with their two positive charges and requirement for two non-bridging oxygen ions to compensate for their charge, are much less mobile themselves and also hinder diffusion of other ions, especially the alkalis. The most common commercial glasses contain both alkali and alkaline earth ions (usually sodium and calcium), for easier processing and satisfying corrosion resistance.9 Corrosion resistance of glass can be achieved by dealkalization, removal of the alkali ions from the glass surface by reaction with e.g. sulfur or fluorine compounds. Presence of alkaline metal ions has also detrimental effect to the loss tangent of the glass, and to its electrical resistance; glasses for electronics (sealing, vacuum tubes, lamps...) have to take this in account. Addition of lead(II) oxide lowers melting point, lowers viscosity of the melt, and increases refractive index. Lead oxide also facilitates solubility of other metal oxides and therefore is used in colored glasses. The viscosity decrease of lead glass melt is very significant (roughly 100 times in comparison with soda glasses); this allows easier removal of bubbles and working at lower temperatures, hence its frequent use as an additive in vitreous enamels and glass solders. The high ionic radius of the Pb2+ ion renders it highly immobile in the matrix and hinders the movement of other ions; lead glasses therefore have high electrical resistance, about two orders of magnitude higher than soda-lime glass (108.5 vs 106.5 Ohm·cm, DC at 250 °C). For more details, see lead glass.10 Addition of fluorine lowers the dielectric constant of glass. Fluorine is highly electronegative and attracts the electrons in the lattice, lowering the polarizability of the material. Such silicon dioxide-fluoride is used in manufacture of integrated circuits as an insulator. High levels of fluorine doping lead to formation of volatile SiF2O and such glass is then thermally unstable. Stable layers were achieved with dielectric constant down to about 3.5–3.7.11 Amorphous metals Samples of amorphous metal, with centimeter scale In the past, small batches of amorphous metals with high surface area configurations (ribbons, wires, films, etc.) have been produced through the implementation of extremely rapid rates of cooling. This was initially termed "splat cooling" by doctoral student W. Klement at Caltech, who showed that cooling rates on the order of millions of degrees per second is sufficient to impede the formation of crystals, and the metallic atoms becomes "locked into" a glassy state. Amorphous metal wires have been produced by sputtering molten metal onto a spinning metal disk. More recently a number of alloys have been produced in layers with thickness exceeding 1 millimeter. These are known as bulk metallic glasses (BMG). Liquidmetal Technologies sell a number of titanium-based BMGs. Batches of amorphous steel have also been produced that demonstrate mechanical properties far exceeding those found in conventional steel alloys.121314 In 2004, NIST researchers presented evidence that an isotropic non-crystalline metallic phase (dubbed "q-glass") could be grown from the melt. This phase is the first phase, or "primary phase," to form in the Al-Fe-Si system during rapid cooling. Interestingly, experimental evidence indicates that this phase forms by a first-order transition. Transmission electron microscopy (TEM) images show that the q-glass nucleates from the melt as discrete particles, which grow spherically with a uniform growth rate in all directions. The diffraction pattern shows it to be an isotropic glassy phase. Yet there is a nucleation barrier, which implies an interfacial discontinuity (or internal surface) between the glass and the melt.15 Electrolytes Electrolytes or molten salts are mixtures of different ions. In a mixture of three or more ionic species of dissimilar size and shape, crystallization can be so difficult that the liquid can easily be supercooled into a glass. The best studied example is Ca0.4K0.6(NO3)1.4. Aqueous solutions Some aqueous solutions can be supercooled into a glassy state, for instance LiCl:RH2O in the composition range 4<R<8. Molecular liquids A molecular liquid is composed of molecules that do not form a covalent network but interact only through weak van der Waals forces or through transient hydrogen bonds. Many molecular liquids can be supercooled into a glass; some are excellent glass formers that normally do not crystallize. A widely known example is sugar glass. Under extremes of pressure and temperature solids may exhibit large structural and physical changes which can lead to polyamorphic phase transitions.16 In 2006 Italian scientists created an amorphous phase of carbon dioxide using extreme pressure. The substance was named amorphous carbonia(a-CO2) and exhibits an atomic structure resembling that of silica.17 Polymers Colloidal glasses Concentrated colloidal suspensions may exhibit a distinct glass transition as function of particle concentration or density.18 Glass-ceramics A high strength glass-ceramic cooktop with negligible thermal expansion. Glass-ceramic materials share many properties with both non-crystalline glass and crystalline ceramics. They are formed as a glass, and then partially crystallized by heat treatment. For example, the microstructure of whiteware ceramics frequently contains both amorphous and crystalline phases. Crystalline grains are often embedded within a non-crystalline intergranular phase of grain boundaries. When applied to whiteware ceramics, vitreous means the material has an extremely low permeability to liquids, often but not always water, when determined by a specified test regime.1920 The term mainly refers to a mix of lithium and aluminosilicates which yields an array of materials with interesting thermomechanical properties. The most commercially important of these have the distinction of being impervious to thermal shock. Thus, glass-ceramics have become extremely useful for countertop cooking. The negative thermal expansion coefficient (TEC) of the crystalline ceramic phase can be balanced with the positive TEC of the glassy phase. At a certain point (~70% crystalline) the glass-ceramic has a net TEC near zero. This type of glass-ceramic exhibits excellent mechanical properties and can sustain repeated and quick temperature changes up to 1000 °C.1920 Structure Main article: Structure of liquids and glasses The amorphous structure of glassy Silica (SiO2) in two dimensions. No long range order is present, however there is local ordering with respect to the tetrahedral arrangement of Oxygen (O) atoms around the Silicon (Si) atoms. As in other amorphous solids, the atomic structure of a glass lacks any long range translational periodicity. However, due to chemical bonding characteristics glasses do possess a high degree of short-range order with respect to local atomic polyhedra.21 Glass versus supercooled liquid Main article: glass transition Unsolved problems in physics What is the nature of the transition between a fluid or regular solid and a glassy phase? "The deepest and most interesting unsolved problem in solid state theory is probably the theory of the nature of glass and the glass transition." P.W. Anderson22 In physics, the standard definition of a glass (or vitreous solid) is a solid formed by rapid melt quenching.2324252627 However, the term glass is often used to describe any amorphous solid that exhibits a glass transition temperature Tg. If the cooling is sufficiently rapid (relative to the characteristic crystallization time) then crystallization is prevented and instead the disordered atomic configuration of the supercooled liquid is frozen into the solid state at Tg. Generally, the structure of a glass exists in a metastable state with respect to its crystalline form, although in certain circumstances, for example in atactic polymers, there is no crystalline analogue of the amorphous phase.28 Glass is an amorphous solid. It exhibits an atomic structure close to that observed in the supercooled liquid phase but displays all the mechanical properties of a solid.2930 The notion that glass flows to an appreciable extent over extended periods of time is not supported by empirical research or theoretical analysis (see viscosity of amorphous materials). Some people consider glass to be a liquid due to its lack of a first-order phase transition2931 where certain thermodynamic variables such as volume, entropy and enthalpy are discontinuous through the glass transition range. However, the glass transition may be described as analogous to a second-order phase transition where the intensive thermodynamic variables such as the thermal expansivity and heat capacity are discontinuous.32 Despite this, the equilibrium theory of phase transformations does not entirely hold for glass, and hence the glass transition cannot be classed as one of the classical equilibrium phase transformations in solids.2633 Although the atomic structure of glass shares characteristics of the structure in a supercooled liquid, glass tends to behave as a solid below its glass transition temperature.34 A supercooled liquid behaves as a liquid, but it is below the freezing point of the material, and in some cases will crystallize almost instantly if a crystal is added as a core. The change in heat capacity at a glass transition and a melting transition of comparable materials are typically of the same order of magnitude, indicating that the change in active degrees of freedom is comparable as well. Both in a glass and in a crystal it is mostly only the vibrational degrees of freedom that remain active, whereas rotational and translational motion is arrested. This helps to explain why both crystalline and non-crystalline solids exhibit rigidity on most experimental time scales. Behavior of antique glass The observation that old windows are sometimes found to be thicker at the bottom than at the top is often offered as supporting evidence for the view that glass flows over a timescale of centuries. The assumption being that the glass was once uniform, but has flowed to its new shape, which is a property of liquid.35 However, this assumption is incorrect; glass does not flow. The reason for the observation is that in the past, when panes of glass were commonly made by glassblowers, the technique used was to spin molten glass so as to create a round, mostly flat and even plate (the crown glass process, described above). This plate was then cut to fit a window. The pieces were not, however, absolutely flat; the edges of the disk became thicker as the glass spun. When installed in a window frame, the glass would be placed thicker side down both for the sake of stability and to prevent water accumulating in the lead cames at the bottom of the window.36 Occasionally such glass has been found thinner side down or thicker on either side of the window's edge, the result of carelessness during installation.37 Mass production of glass window panes in the early twentieth century caused a similar effect. In glass factories, molten glass was poured onto a large cooling table and allowed to spread. The resulting glass is thicker at the location of the pour, located at the center of the large sheet. These sheets were cut into smaller window panes with nonuniform thickness, typically with the location of the pour centred in one of the panes (known as "bull's-eyes") for decorative effect. Modern glass intended for windows is produced as float glass and is very uniform in thickness. Several other points can be considered which contradict the "cathedral glass flow" theory: Writing in the American Journal of Physics, physicist Edgar D. Zanotto states "...the predicted relaxation time for GeO2 at room temperature is 1032 years. Hence, the relaxation period (characteristic flow time) of cathedral glasses would be even longer."38 (1032 years is many times longer than the estimated age of the Universe.) If medieval glass has flowed perceptibly, then ancient Roman and Egyptian objects should have flowed proportionately more — but this is not observed. Similarly, prehistoric obsidian blades should have lost their edge; this is not observed either (although obsidian may have a different viscosity from window glass).29 If glass flows at a rate that allows changes to be seen with the naked eye after centuries, then the effect should be noticeable in antique telescopes. Any slight deformation in the antique telescopic lenses would lead to a dramatic decrease in optical performance, a phenomenon that is not observed.29 There are many examples of centuries-old glass shelving which has not bent, even though it is under much higher stress from gravitational loads than vertical window glass. The above does not apply to materials that have a glass transition temperature close to room temperature, such as certain plastics used in daily life like polystyrene and polypropylene. Over time, they may well show viscoelastic behaviour, and this is a serious concern when applying these materials in construction. Physical properties See also: List of physical properties of glass Optical properties Glass is in widespread use largely due to the production of glass compositions that are transparent to visible wavelengths of light. In contrast, polycrystalline materials do not in general transmit visible light.39 The individual crystallites may be transparent, but their facets (grain boundaries) reflect or scatter light resulting in diffuse reflection. Glass does not contain the internal subdivisions associated with grain boundaries in polycrystals and hence does not scatter light in the same manner as a polycrystalline material. The surface of a glass is often smooth since during glass formation the molecules of the supercooled liquid are not forced to dispose in rigid crystal geometries and can follow surface tension, which imposes a microscopically smooth surface. These properties, which give glass its clearness, can be retained even if glass is partially light-absorbing i.e. colored.40 Glass has the ability to refract, reflect and transmit light following geometrical optics, without scattering it, and it is used in the manufacture of lenses and windows. Common glass has a refraction index around 1.5. According to Fresnel equations, the reflectivity of a sheet of glass is about 4% per surface (at normal incidence), and its transmissivity about 92%. Glass also finds application in optoelectronics e.g. for light transmitting optical fibres. Color Main article: Glass coloring and color marking Common soda-lime float glass appears green in thick sections because of Fe2+ impurities. Color in glass may be obtained by addition of electrically charged ions (or color centers) that are homogeneously distributed, and by precipitation of finely dispersed particles (such as in photochromic glasses).41 Ordinary soda-lime glass appears colorless to the naked eye when it is thin, although iron(II) oxide (FeO) impurities of up to 0.1 wt%42 produce a green tint which can be viewed in thick pieces or with the aid of scientific instruments. Further FeO and Cr2O3 additions may be used for the production of green bottles. Sulfur, together with carbon and iron salts, is used to form iron polysulfides and produce amber glass ranging from yellowish to almost black.43 Manganese dioxide can be added in small amounts to remove the green tint given by iron(II) oxide. Glass art Main article: Studio glass Main article: Art glass Main article: Glass art A vase being created at the Reijmyre glassworks, Sweden Paperweight with items inside the glass, Corning Museum of Glass A glass sculpture by Dale Chihuly, “The Sun” at the “Gardens of Glass” exhibition in Kew Gardens, London. The piece is 13 feet (4 metres) high and made from 1000 separate glass objects. Glass tiles mosaic (detail). From the 19th century, various types of fancy glass started to become significant branches of the decorative arts. Cameo glass was revived for the first time since the Romans, initially mostly used for pieces in a neo-classical style. The Art Nouveau movement in particular made great use of glass, with René Lalique, Émile Gallé, and Daum of Nancy important names in the first French wave of the movement, producing colored vases and similar pieces, often in cameo glass, and also using lustre techniques. Louis Comfort Tiffany in America specialized in secular stained glass, mostly of plant subjects, both in panels and his famous lamps. From the 20th century, some glass artists began to class themselves as in effect sculptors working in glass, and as part of the fine arts. Several of the most common techniques for producing glass art include: blowing, kiln-casting, fusing, slumping, pate-de-verre, flame-working, hot-sculpting and cold-working. Cold work includes traditional stained glass work as well as other methods of shaping glass at room temperature. Glass can also be cut with a diamond saw, or copper wheels embedded with abrasives, and polished to give gleaming facets; the technique used in creating Waterford crystal.44 Art is sometimes etched into glass via the use of acid, caustic, or abrasive substances. Traditionally this was done after the glass was blown or cast. In the 1920s a new mould-etch process was invented, in which art was etched directly into the mould, so that each cast piece emerged from the mould with the image already on the surface of the glass. This reduced manufacturing costs and, combined with a wider use of colored glass, led to cheap glassware in the 1930s, which later became known as Depression glass.45 As the types of acids used in this process are extremely hazardous, abrasive methods have gained popularity. Another technique is devitrification. Objects made out of glass include not only traditional objects such as vessels (bowls, vases, bottles, and other containers), paperweights, marbles, beads, but an endless range of sculpture and installation art as well. Colored glass is often used, though sometimes the glass is painted, innumerable examples exist of the use of stained glass. Museums Apart from historical collections in general museums, modern works of art in glass can be seen in a variety of museums, including the Chrysler Museum, the Museum of Glass in Tacoma, the Metropolitan Museum of Art, the Toledo Museum of Art, and Corning Museum of Glass, in Corning, NY, which houses the world's largest collection of glass art and history, with more than 45,000 objects in its collection.46 The Harvard Museum of Natural History has a collection of extremely detailed models of flowers made of painted glass. These were lampworked by Leopold Blaschka and his son Rudolph, who never revealed the method he used to make them. The Blaschka Glass Flowers are still an inspiration to glassblowers today.47 See also Fiberglass Superglass Tektite Volcanic glass Vitrified sand Prince Rupert's Drops Kimberley Points References ^ "Glass Online: The History of Glass". http://www.glassonline.com/infoserv/history.html. Retrieved 2010-09-30.  ^ Douglas, R. W. (1972). A history of glassmaking. Henley-on-Thames: G T Foulis & Co Ltd. ISBN 0854291172.  ^ a b c B. H. W. S. de Jong, "Glass"; in "Ullmann's Encyclopedia of Industrial Chemistry"; 5th edition, vol. A12, VCH Publishers, Weinheim, Germany, 1989, ISBN 3-527-20112-5, pp. 365–432. ^ http://www.siliconwafers.net/optical-glass.htm Properties of optical glasses ^ "PFG Glass". Pfg.co.za. http://www.pfg.co.za/about%20glass.htm. Retrieved 2009-10-24.  ^ a b "Glass melting, Pacific Northwest National Laboratory". Depts.washington.edu. http://depts.washington.edu/mti/1999/labs/glass_ceramics/mst_glass.html. Retrieved 2009-10-24.  ^ Alexander Fluegel. "Glass melting in the laboratory". Glassproperties.com. http://glassproperties.com/melting/. Retrieved 2009-10-24.  ^ Greer, A. Lindsay; Mathur, N (2005). "Materials science: Changing face of the chameleon". Nature 437 (7063): 1246–1247. doi:10.1038/4371246a. PMID 16251941.  ^ Eric Le Bourhis (2007). Glass: Mechanics and Technology. Wiley-VCH. p. 74. ISBN 3527315497. http://books.google.com/?id=34W4ZNDBHqQC&pg=PA64&dq=%22borate+glass%22&cd=1#v=onepage&q=%22borate%20glass%22.  ^ James F. Shackelford, Robert H. Doremus (2008). Ceramic and Glass Materials: Structure, Properties and Processing. Springer. p. 158. ISBN 0387733612. http://books.google.com/?id=ASIYuNCp81YC&pg=PA158&dq=%22glass+solders%22&cd=3#v=onepage&q=%22glass%20solders%22.  ^ Robert Doering, Yoshio Nishi (2007). Handbook of semiconductor manufacturing technology. CRC Press. pp. 12–3. ISBN 1574446754. http://books.google.com/?id=PsVVKz_hjBgC&pg=SA12-PA3&dq=semiconductor+failure+microphotograph&cd=5#v=onepage&q=.  ^ Klemens, W. and Duwez, P., Non-crystalline Structure in Solidified Gold-Silicon Alloys, Nature, Vol. 187, p. 869 (1960) ^ Libermann H. and Graham C., Production of Amorphous Alloy Ribbons and Effects of Apparatus Parameters On Ribbon Dimensions, IEEE Transactions on Magnetics, Vol. 12 (1976) ^ V. Ponnambalam, S. Joseph Poon and Gary J. Shiflet (2004). "Fe-based bulk metallic glasses with diameter thickness larger than one centimeter". Journal of Materials Research 19 (5): 1320. doi:10.1557/JMR.2004.0176. http://lucy.mrs.org/publications/jmr/jmra/2004/may/0176.html.  ^ "Metallurgy Division Publications – NISTIR 7127". http://www.metallurgy.nist.gov/techactv2004/TechnicalHighlights.html#glass. ; Mendelev, M.I., et al., Interface Mobility and the Liquid-Glass Transition in a One-Component System, Phys. Rev. B, Vol. 74, p. 104206 (2006) ^ P. F. McMillan (2004). "Polyamorphic transformations in liquids and glasses". Journal of Materials Chemistry 14: 1506–1512. doi:10.1039/b401308p.  ^ carbon dioxide glass created in the lab 15 June 2006, www.newscientisttech.com. Retrieved 3 August 2006. ^ Pusey, P.N. and van Megen, W., Phys. Rev. Lett., Vol. 59, p. 2083 (1987); van Megan, W. and Underwood, S.M., Phys. Rev. E, Vol. 47, p. 248 (1993) and references therein; Löwen, H., Dynamics of Charged Colloidal Suspensions Across the Freezing and Glass Transition, in Ordering and Phase Transitions in Charged Colloids, Arora, A.k. and Tat, B.V.R., Eds. (VCH Publishers, New York, 1996) ^ a b Kingery, W,D., Bowen, H.K., and Uhlmann, D.R., Introduction to Ceramics, 2nd Edn. (John Wiley & Sons, New York, 2006) ^ a b Richerson, D.W., Modern Ceramic Engineering,2nd Ed., (Marcel Dekker Inc., 1992) ISBN 0-8247-8634-3. ^ P.S. Salmon (2002). "Order within disorder". Nature Materials 1 (2): 87. doi:10.1038/nmat737. PMID 12618817.  ^ P W Anderson (1995). Science 267: 1615  ^ ASTM definition of glass from 1945; also: DIN 1259, Glas – Begriffe für Glasarten und Glasgruppen, September 1986 ^ Zallen, R. (1983). The Physics of Amorphous Solids. New York: John Wiley. ISBN 0471019682.  ^ Cusack, N. E. (1987). The physics of structurally disordered matter: an introduction. Adam Hilger in association with the University of Sussex press. ISBN 0852748299.  ^ a b Elliot, S. R. (1984). Physics of Amorphous Materials. Longman group ltd.  ^ Horst Scholze (1991). Glass – Nature, Structure, and Properties. Springer. ISBN 0-387-97396-6.  ^ Folmer, J. C. W.; Franzen, Stefan (2003). "Study of polymer glasses by modulated differential scanning calorimetry in the undergraduate physical chemistry laboratory". Journal of Chemical Education 80 (7): 813. doi:10.1021/ed080p813. http://jchemed.chem.wisc.edu/Journal/Issues/2003/Jul/abs813.html.  ^ a b c d Philip Gibbs. "Is glass liquid or solid?". http://math.ucr.edu/home/baez/physics/General/Glass/glass.html. Retrieved 2007-03-21.  ^ "Philip Gibbs" Glass Worldwide, (May/June 2007), pp. 14–18 ^ Jim Loy. "Glass Is A Liquid?". http://www.jimloy.com/physics/glass.htm. Retrieved 2007-03-21.  ^ M.I. Ojovan, W.E. Lee (2006). "Topologically disordered systems at the glass transition". J. Phys.: Condensed Matter 18: 11507–11520. doi:10.1088/0953-8984/18/50/007.  ^ Horst Scholze (1991). Glass – Nature, Structure, and Properties. Springer. ISBN 0-387-97396-6.  ^ Florin Neumann. "Glass: Liquid or Solid – Science vs. an Urban Legend". http://dwb.unl.edu/Teacher/NSF/C01/C01Links/www.ualberta.ca/~bderksen/florin.html. Retrieved 2007-04-08.  ^ Chang, Kenneth (2008-07-29). "The Nature of Glass Remains Anything but Clear". New York Times. http://www.nytimes.com/2008/07/29/science/29glass.html?ex=1375070400&en=048ade4011756b24&ei=5124&partner=permalink&exprod=permalink. Retrieved 2008-07-29.  ^ "Dr Karl's Homework: Glass Flows". Abc.net.au. 2000-01-26. http://www.abc.net.au/science/k2/homework/s95602.htm. Retrieved 2009-10-24.  ^ H. Halem. "Does Glass Flow". http://www.glassnotes.com/WindowPanes.html. Retrieved 2010-09-02.  ^ Zanotto, Edgar Dutra (1998). "Do Cathedral Glasses Flow?". American Journal of Physics 66: 392–396. doi:10.1119/1.19026.  ^ Barsoum, M.W., Fundamentals of Ceramics, Institute of Physics: Series in Materials Science and Engineering (Taylor and Francis, 2002) ^ Uhlmann, D.R. and Kreidl, N.J., Optical Properties of Glass (American Ceramic Society, 1991) ^ Werner Vogel (1994). Glass Chemistry (2 ed.). Springer-Verlag Berlin and Heidelberg GmbH & Co. K. ISBN 3540575723.  ^ "High temperature glass melt property database for process modeling"; Eds.: Thomas P. Seward III and Terese Vascott; The American Ceramic Society, Westerville, Ohio, 2005, ISBN 1-57498-225-7 ^ Substances Used in the Making of Coloured Glass 1st.glassman.com (David M Issitt). Retrieved 3 August 2006. ^ "Waterford Crystal Visitors Centre". http://www.waterfordvisitorcentre.com/. Retrieved 2007-10-19.  ^ "Depression Glass". http://www.glassonweb.com/articles/article/201/. Retrieved 2007-10-19.  ^ "Corning Museum of Glass". Archived from the original on 2008-01-12. http://web.archive.org/web/20080112004034/http://www.cmog.org/index.asp?pageId=1276. Retrieved 2007-10-14.  ^ the Harvard Museum of Natural History's page on the exhibitdead link Bibliography Ghosh, Amalananda (1990). An Encyclopaedia of Indian Archaeology. BRILL. ISBN 9004092625.  Gowlett, J.A.J. (1997). High Definition Archaeology: Threads Through the Past. Routledge. ISBN 0415184290.  Noel C. Stokes; The Glass and Glazing Handbook; Standards Australia; SAA HB125–1998 Stookey, D.Donald. Explorations in Glass: An Autobiography. Wiley, 2000. ISBN 978-1-57498-124-7 Vogel, Werner. Chemistry of Glass. Wiley, 1985. ISBN 978-0-916094-73-7 External links Wikimedia Commons has media related to: Glass Wikisource has the text of the 1911 Encyclopædia Britannica article Glass. Glass Encyclopedia – A comprehensive guide to all types of antique and collectable glass, with information, pictures and references The Canadian Museum of Civilization – The Story of Glass Making in Canada Corning Museum of Glass "How Your Glass Ware Is Made" by George W. Waltz, February 1951, Popular Science v · d · eGlass science topics Basics Glass · Glass transition · Supercooling Glass formulation AgInSbTe · Bioglass · Borophosphosilicate glass · Borosilicate glass · Ceramic glaze · Chalcogenide glass · Cobalt glass · Cranberry glass · Crown glass · Flint glass · Fluorosilicate glass · Fused quartz · GeSbTe · Gold ruby glass · Lead glass · Milk glass · Phosphosilicate glass · Photochromic lens glass · Silicate glass · Soda-lime glass · Sodium hexametaphosphate · Soluble glass · Tellurite glass · Ultra low expansion glass · Uranium glass · Vitreous enamel · Wood's glass · ZBLAN Glass-ceramics Bioactive glass · CorningWare · Glass-ceramic-to-metal seals · Macor · Zerodur Glass preparation Annealing · Chemical vapor deposition · Glass batch calculation · Glass forming · Glass melting · Glass modeling · Ion implantation · Liquidus temperature · Sol-gel technique · Viscosity · Vitrification Optics Achromat · Dispersion · Gradient index optics · Hydrogen darkening · Optical amplifier · Optical fiber · Optical lens design · Photochromic lens · Photosensitive glass · Refraction · Transparent materials Surface modification Anti-reflective coating · Chemically strengthened glass · Corrosion · Dealkalization · DNA microarray · Hydrogen darkening · Insulated glazing · Porous glass · Self-cleaning glass · Sol-gel technique · Toughened glass Diverse topics Glass-coated wire · Glass databases · Glass electrode · Glass fiber reinforced concrete · Glass ionomer cement · Glass microspheres · Glass-reinforced plastic · Glass science institutes · Glass-to-metal seal · Porous glass · Prince Rupert's Drops · Radioactive waste vitrification · Windshield v · d · eGlass forming techniques Commercial techniques Float glass process · Blowing and pressing (containers) · Extrusion / Drawing (fibers, glasswool) · Drawing (optical fibers) · Precision glass moulding · Overflow downdraw method · Pressing · Casting · Cutting · Flame polishing · Chemical polishing · Diamond turning · Rolling Artistic and historic techniques Beadmaking · Blowing · Blown plate · Broad sheet · Caneworking · Crown glass · Cylinder blown sheet · Engraving  · Etching · Fourcault process · Fusing · Lampworking · Machine drawn cylinder sheet · Millefiori · Polished plate · Slumping · Stained glass fusing · Stained glass production See also Glossary of glass art terms v · d · eGlass makers and brands Contemporary companies Anchor Hocking · Arc International · Ardagh · Armashield · Asahi · Aurora Glass Foundry · Baccarat · Blenko Glass Company · Bodum · Corning · Dartington Crystal · Daum · Edinburgh Crystal · Fanavid · Fenton Art Glass Company · Firozabad glass industry · Franz Mayer · Glava · Glaverbel · Hardman & Co. · Heaton, Butler and Bayne · Holmegaard Glassworks · Holophane · Hoya · Kingdom of Crystal · Kokomo Opalescent Glass Works · Kosta Glasbruk · Libbey Owens Ford · Liuli Gongfang · Iittala · Luoyang · Johns Manville · Mats Jonasson Målerås · Moser Glass · Mosser Glass · Nippon Sheet Glass · Ohara · Orrefors Glasbruk · Osram · Owens Corning · Owens-Illinois · Pauly & C. - Compagnia Venezia Murano · Phu Phong · Pilkington · PPG · Preciosa · Quinn Group · Riedel · Royal Leerdam Crystal · Saint-Gobain · Samsung Corning Precision Glass · Schonbek · Schott · Shrigley and Hunt · Steuben Glass · Sterlite Optical Technologies · Swarovski · Tyrone Crystal · Val Saint Lambert · Verrerie of Brehat · Waterford · Watts & Co · World Kitchen · Xinyi Glass · Zwiesel Historic companies Bakewell Glass · Belmont Glass Company · Boston and Sandwich Glass Company · Brockway Glass · Carr Lowrey Glass Company · Cambridge Glass · Chance Brothers · Clayton and Bell · Duncan & Miller · Dunbar Glass · Fostoria Glass Company · General Glass Industries · Alexander Gibbs · Grönvik glasbruk · Hazel-Atlas · Heisey · Hemingray Glass Company · Knox Glass Bottle Company · Lavers, Barraud and Westlake · Manufacture royale de glaces de miroirs · Morris & Co. · Old Dominion Glass Company · James Powell and Sons · Ravenhead glass · The Root Glass Company · Sneath Glass Company · Ward and Hughes · Westmoreland Glass Company · Wheaton Industries  · Whitall Tatum Company · White Glass Company · Worshipful Company Glassmakers John Adams · Richard M. Atwater · Frederick Carder · Irving Wightman Colburn · Henry Crimmel · Henry Clay Fry · Friedrich · A. H. Heisey · Libbey · Antonio Neri · Alastair Pilkington · Salviati · Otto Schott · S. Donald Stookey · W. E. S. Turner · John M. Whitall Trademarks and brands Bohemian glass · Bomex · Burmese glass · Chevron bead · Corelle · CorningWare · Cranberry glass · Cristallo · Duran · Endural · Favrile · Fire King · Gold Ruby · MACOR · Murano glass · Opaline glass · Pyrex · Ravenhead glass · Tiffany glass · Vitrite · Vitrolite · Vycor · Waterford Crystal · Wood's glass · Zerodur