Editing Glass (section)

=== Silicate glasses ===
[[File:Quartz sand.jpg|thumb|[[Sand|Quartz sand]] (silica) is the main raw material in commercial glass production|alt=Close-up photograph of sand]]
[[Silicon dioxide]] (SiO<sub>2</sub>) is a common fundamental constituent of glass. [[Fused quartz]] is a glass made from chemically pure silica.<ref name="Chawla93" /> It has very low thermal expansion and excellent resistance to [[thermal shock]], being able to survive immersion in water while red hot, resists high temperatures (1000–1500&nbsp;°C) and chemical weathering, and is very hard. It is also transparent to a wider spectral range than ordinary glass, extending from the visible further into both the [[UV]] and [[Infrared|IR]] ranges, and is sometimes used where transparency to these wavelengths is necessary. Fused quartz is used for high-temperature applications such as furnace tubes, lighting tubes, melting crucibles, etc.<ref name="Seafriends-1994">{{cite web|url=http://www.seafriends.org.nz/oceano/seasand.htm|title=Mining the sea sand|url-status=live|archive-url=https://web.archive.org/web/20120229061512/http://www.seafriends.org.nz/oceano/seasand.htm|archive-date=29 February 2012|website=Seafriends|date=1994-02-08|access-date=2012-05-15}}</ref> However, its high melting temperature (1723&nbsp;°C) and viscosity make it difficult to work with. Therefore, normally, other substances (fluxes) are added to lower the melting temperature and simplify glass processing.<ref name="Chemistry-explained">{{cite web|url=http://www.chemistryexplained.com/Ge-Hy/Glass.html|access-date=1 April 2015|title=Glass – Chemistry Encyclopedia|url-status=live|archive-url=https://web.archive.org/web/20150402113454/http://www.chemistryexplained.com/Ge-Hy/Glass.html|archive-date=2 April 2015}}</ref>

==== Soda–lime glass ====
{{Main|Soda–lime glass}}
[[Sodium carbonate]] (Na<sub>2</sub>CO<sub>3</sub>, "soda") is a common additive and acts to lower the glass-transition temperature. However, [[sodium silicate]] is [[water solubility|water-soluble]], so [[lime (mineral)|lime]] (CaO, [[calcium oxide]], generally obtained from [[limestone]]), along with [[magnesium oxide]] (MgO), and [[aluminium oxide]] (Al<sub>2</sub>O<sub>3</sub>), are commonly added to improve chemical durability. Soda–lime glasses (Na<sub>2</sub>O) + lime (CaO) + magnesia (MgO) + alumina (Al<sub>2</sub>O<sub>3</sub>) account for over 75% of manufactured glass, containing about 70 to 74% silica by weight.<ref name="Chawla93" /><ref name="ullmann">B.H.W.S. de Jong, "Glass"; in "Ullmann's Encyclopedia of Industrial Chemistry"; 5th edition, vol. A12, VCH Publishers, Weinheim, Germany, 1989, {{ISBN|978-3-527-20112-9}}, pp. 365–432.</ref> Soda–lime–silicate glass is transparent, easily formed, and most suitable for window glass and tableware.<ref name="Spence-2016">{{Cite book|url=https://books.google.com/books?id=KX5TCwAAQBAJ&pg=PA509|title=Construction Materials, Methods and Techniques|last1=Spence|first1=William P.|last2=Kultermann|first2=Eva|year=2016|publisher=Cengage Learning|isbn=978-1-305-08627-2|pages=510–526}}</ref> However, it has a high thermal expansion and poor resistance to heat.<ref name="Spence-2016" /> Soda–lime glass is typically used for [[window]]s, [[bottle]]s, [[light bulb]]s, and [[jar]]s.<ref name="Chemistry-explained" />

==== Borosilicate glass ====
[[File:Measuring cup.jpg|thumb|A [[Pyrex]] [[borosilicate glass]] [[measuring cup]] |alt=Refer to caption]]
[[Borosilicate glass]]es (e.g. [[Pyrex]], [[Duran (glass)|Duran]]) typically contain 5–13% [[boron trioxide]] (B<sub>2</sub>O<sub>3</sub>).<ref name="Chemistry-explained" /> Borosilicate glasses have fairly low [[Coefficient of thermal expansion|coefficients of thermal expansion]] (7740 Pyrex CTE is 3.25{{e|-6}}/°C<ref>{{cite web|url=http://www.quartz.com/pxprop.pdf|title=Properties of PYREX®, PYREXPLUS® and Low Actinic PYREX Code 7740 Glasses|publisher=Corning, Inc.|url-status=live|archive-url=https://web.archive.org/web/20120113050839/http://www.quartz.com/pxprop.pdf|archive-date=13 January 2012|access-date=2012-05-15}}</ref> as compared to about 9{{e|-6}}/°C for a typical soda–lime glass<ref>{{cite web|url=http://www.us.schott.com/tubing/media/selector/datasheets/english/schott-tubing_datasheet_ar-glas_english.pdf|title=AR-GLAS® Technical Data|url-status=live|archive-url=https://web.archive.org/web/20120612224929/http://www.us.schott.com/tubing/media/selector/datasheets/english/schott-tubing_datasheet_ar-glas_english.pdf|archive-date=12 June 2012|publisher=Schott, Inc.}}</ref>). They are, therefore, less subject to [[Stress (mechanics)|stress]] caused by [[thermal expansion]] and thus less vulnerable to [[Crack propagation|cracking]] from [[thermal shock]]. They are commonly used for e.g. [[labware]], [[cookware|household cookware]], and sealed beam car [[head lamp]]s.<ref name="Chemistry-explained" />

==== Lead glass ====
{{Main|Lead glass}}{{See also|Lead poisoning}}
The addition of [[lead(II) oxide]] into silicate glass lowers the melting point and [[viscosity]] of the melt.<ref>{{Cite book |url=https://books.google.com/books?id=ZeF_QLW6-xsC&pg=PA125 |title=Introduction to Glass Science and Technology |last=Shelby |first=J.E. |year=2017 |page=125 |publisher=Royal Society of Chemistry |isbn=978-0-85404-639-3}}</ref> The high density of lead glass (silica + lead oxide (PbO) + potassium oxide (K<sub>2</sub>O) + soda (Na<sub>2</sub>O) + zinc oxide (ZnO) + alumina) results in a high electron density, and hence high refractive index, making the look of glassware more brilliant and causing noticeably more [[specular reflection]] and increased [[Dispersion (optics)|optical dispersion]].<ref name="Chawla93" /><ref name="Schwartz-2002">{{Cite book |url=https://books.google.com/books?id=0ETMBQAAQBAJ&pg=PA352 |title=Encyclopedia of Materials, Parts and Finishes |edition=Second |last=Schwartz |first=Mel |year=2002 |page =352 |publisher=CRC Press |isbn=978-1-4200-1716-8}}</ref> Lead glass has a high elasticity, making the glassware more workable and giving rise to a clear "ring" sound when struck. However, lead glass cannot withstand high temperatures well.<ref name="Seafriends-1994" /> Lead oxide also facilitates the solubility of other metal oxides and is used in coloured glass. The viscosity decrease of lead glass melt is very significant (roughly 100 times in comparison with soda glass); this allows easier removal of bubbles and working at lower temperatures, hence its frequent use as an additive in [[vitreous enamel]]s and [[glass solder]]s. The high [[ionic radius]] of the Pb<sup>2+</sup> ion renders it highly immobile and hinders the movement of other ions; lead glasses therefore have high electrical resistance, about two orders of magnitude higher than soda–lime glass (10<sup>8.5</sup> vs 10<sup>6.5</sup>&nbsp;Ω⋅cm, [[direct current|DC]] at 250&nbsp;°C).<ref>{{Cite book|url=https://books.google.com/books?id=ASIYuNCp81YC&pg=PA158|title=Ceramic and Glass Materials: Structure, Properties and Processing|last1=Shackelford|first1=James F.|last2=Doremus|first2=Robert H.|date=2008-04-12|publisher=Springer Science & Business Media|isbn=978-0-387-73362-3 |page=158}}</ref>

==== Aluminosilicate glass ====
Aluminosilicate glass typically contains 5–10% [[alumina]] (Al<sub>2</sub>O<sub>3</sub>). Aluminosilicate glass tends to be more difficult to melt and shape compared to borosilicate compositions but has excellent thermal resistance and durability.<ref name="Chemistry-explained" /> Aluminosilicate glass is extensively used for [[fiberglass|fibreglass]],<ref name="Askeland-2008">{{Cite book|url=https://books.google.com/books?id=TL4j-jDXsk0C&pg=PA485|title=Essentials of Materials Science & Engineering|last1=Askeland|first1=Donald R.|last2=Fulay|first2=Pradeep P.|year=2008|page=485|publisher=Cengage Learning|isbn=978-0-495-24446-2}}</ref> used for making glass-reinforced plastics (boats, fishing rods, etc.), top-of-stove cookware, and halogen bulb glass.<ref name="Seafriends-1994" /><ref name="Chemistry-explained" />

==== Other oxide additives ====
The addition of [[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 eyeglasses.<ref>{{cite web|url=http://www.historyofglass.com/glass-making-process/glass-ingredients/|title=Glass Ingredients – What is Glass Made Of?|website=www.historyofglass.com|access-date=2017-04-23|url-status=live|archive-url=https://web.archive.org/web/20170423155431/http://www.historyofglass.com/glass-making-process/glass-ingredients/|archive-date=23 April 2017}}</ref> Iron can be incorporated into glass to absorb [[infrared]] radiation, for example in heat-absorbing filters for movie projectors, while [[cerium(IV) oxide]] can be used for glass that absorbs [[ultraviolet]] wavelengths.<ref>{{cite book |last=Pfaender |first=Heinz G. |title=Schott guide to glass |url=https://books.google.com/books?id=v5q4Hje3iFgC&pg=PA135 |access-date=8 February 2011 |year=1996 |publisher=Springer |isbn=978-0-412-62060-7 |pages=135, 186 |url-status=live |archive-url=https://web.archive.org/web/20130525185349/http://books.google.com/books?id=v5q4Hje3iFgC&pg=PA135 |archive-date=25 May 2013}}</ref> [[Fluorine]] lowers the [[dielectric constant]] of glass. Fluorine is highly [[electronegative]] and lowers the polarizability of the material. Fluoride silicate glasses are used in the manufacture of [[integrated circuit]]s as an insulator.<ref>{{cite book |last1=Doering |first1=Robert |last2=Nishi |first2=Yoshio |url=https://books.google.com/books?id=PsVVKz_hjBgC&pg=SA12-PA3 |title=Handbook of semiconductor manufacturing technology |pages=12–13 |publisher=CRC Press |year=2007 |isbn=978-1-57444-675-3}}</ref>

==== Glass-ceramics ====
{{Main|Glass-ceramic}}
[[File:Ceranfeld.jpg|thumb|A high-strength glass-ceramic [[cooktop]] with negligible [[thermal expansion]] |alt=A cooktop with two of its eyes turned on]]
[[Glass-ceramic]] materials contain both non-crystalline glass and [[Crystallinity|crystalline]] [[ceramic]] phases. They are formed by controlled nucleation and partial crystallisation of a base glass by heat treatment.<ref name="Holand-glass-ceramics">{{cite book |url=https://books.google.com/books?id=Bw_Yz52jdFQC&pg=PA1 |title=Glass Ceramic Technology |last1=Holand |first1=Wolfram |last2=Beall |first2=George H. |year=2012 |pages=1–38 |publisher=John Wiley & Sons |isbn=978-1-118-26592-5}}</ref> Crystalline grains are often embedded within a non-crystalline intergranular phase of [[grain boundary|grain boundaries]]. Glass-ceramics exhibit advantageous thermal, chemical, biological, and dielectric properties as compared to metals or organic polymers.<ref name=Holand-glass-ceramics />

The most commercially important property of glass-ceramics is their imperviousness to thermal shock. Thus, glass-ceramics have become extremely useful for countertop cooking and industrial processes. The negative [[thermal expansion]] coefficient (CTE) of the crystalline ceramic phase can be balanced with the positive CTE of the glassy phase. At a certain point (~70% crystalline) the glass-ceramic has a net CTE near zero. This type of [[glass-ceramic]] exhibits excellent mechanical properties and can sustain repeated and quick temperature changes up to 1000&nbsp;°C.<ref name="MOD">{{cite book |last=Richerson |first=David W. |title=Modern ceramic engineering : properties, processing and use in design |year=1992 |publisher=Dekker |pages=577–578 |location=New York |isbn=978-0-8247-8634-2 |edition=2nd}}</ref><ref name=Holand-glass-ceramics />

==== Fibreglass ====
{{Main|Fiberglass|Glass wool}}
[[Fibreglass]] (also called glass fibre reinforced plastic, GRP) is a [[composite material]] made by reinforcing a plastic [[resin]] with [[glass fibre]]s. It is made by melting glass and stretching the glass into fibres. These fibres are woven together into a cloth and left to set in a plastic resin.<ref name="Parkyn">{{cite book |url=https://books.google.com/books?id=gfEkBQAAQBAJ&pg=PA3 |title=Glass Reinforced Plastics |last=Parkyn |first=Brian |publisher=Elsevier |year=2013 |pages=3–41|isbn=978-1-4831-0298-6 }}</ref><ref>{{cite book |last= Mayer |first= Rayner M. |title= Design with reinforced plastics |page= 7 |publisher= Springer |year= 1993 |url= https://books.google.com/books?id=XQFJego9nGUC&pg=PA7 |isbn= 978-0-85072-294-9}}</ref><ref name="propertiesofmatter">{{cite web|url=http://www.propertiesofmatter.si.edu/teamwork.html|title=Properties of Matter Reading Selection: Perfect Teamwork|website=www.propertiesofmatter.si.edu|access-date=2017-04-25|url-status=dead|archive-url=https://web.archive.org/web/20160512174222/http://www.propertiesofmatter.si.edu/teamwork.html|archive-date=12 May 2016}}</ref>
Fibreglass has the properties of being lightweight and corrosion resistant and is a good [[Insulator (electricity)|insulator]] enabling its use as [[building insulation materials|building insulation material]] and for electronic housing for consumer products. Fibreglass was originally used in the United Kingdom and United States during [[World War II]] to manufacture [[radome]]s. Uses of fibreglass include building and construction materials, boat hulls, car body parts, and aerospace composite materials.<ref name="brittanica-fibreglass">{{Cite web|url=https://www.britannica.com/technology/fiberglass|title=Fibreglass &#124; glass|website=Encyclopedia Britannica|date=28 August 2024 }}</ref><ref name=Parkyn /><ref name=propertiesofmatter />

[[Glass wool|Glass-fibre wool]] is an excellent [[thermal insulation|thermal]] and [[sound insulation|sound]] insulation material, commonly used in buildings (e.g. [[attic]] and [[cavity wall insulation]]), and plumbing (e.g. [[pipe insulation]]), and [[soundproofing]].<ref name=brittanica-fibreglass /> It is produced by forcing molten glass through a fine mesh by [[centripetal force]] and breaking the extruded glass fibres into short lengths using a stream of high-velocity air. The fibres are bonded with an adhesive spray and the resulting wool mat is cut and packed in rolls or panels.<ref name=brittanica-industrial />