Borosilicate Glass

Borosilicate glass is a type of glass with the main glass-forming constituents silica and boron oxide. Borosilicate glasses are known for having very low coefficients of thermal expansion (~3 × 10−6 /°C at 20°C), making them resistant to thermal shock, more so than any other common glass. Such glass is less subject to thermal stress and is commonly used for the construction of reagent bottles. Borosilicate glass is sold under such trade names as Simax, Pyrex, Endural, Schott, or Refmex.



Brosilicate glass was first developed by German glassmaker Otto Schott in the late 19th century[1] and sold under the brand name "Duran" in 1893. After Corning Glass Works introduced Pyrex in 1915, the name became a synonym for borosilicate glass in the English-speaking world.
The European manufacturer of Pyrex, Arc International, uses borosilicate glass in its Pyrex glass kitchen products;[2] however, the U.S. manufacturer of Pyrex kitchenware uses tempered soda-lime glass.[3] Thus Pyrex can refer to either soda-lime glass or borosilicate glass when discussing kitchen glassware, while Pyrex, Bomex, Duran, TGI and Simax all refer to borosilicate glass when discussing laboratory glassware.
Most borosilicate glass is colorless. Colored borosilicate, for the studio glass trade, was first widely brought onto the market in 1986 when Paul Trautman founded Northstar Glassworks.[citation needed] In 2000, former Northstar Glassworks employee Henry Grimmett started Glass Alchemy and developed the first cadmium Crayon Colors and aventurine Sparkle colors in the borosilicate palette.
In addition to the quartz, sodium carbonate, and aluminum oxide traditionally used in glassmaking, boron is used in the manufacture of borosilicate glass. The composition of low expansion borosilicate glass such as those laboratory glasses mentioned above is approximately 80% silica, 13% boric oxide, 4% sodium oxide, and 2-3% aluminum oxide. Though more difficult to make than traditional glass due to the high melting temperature required (Corning conducted a major revamp of their operations to make it), it is economical to produce. Its superior durability, chemical and heat resistance finds excellent use in chemical laboratory equipment, cookware, lighting and, in certain cases, windows.