Borosilicate glass (or sodium-borosilicate glass) is made mainly of silica (70-80%) and boric oxide (7-13%) with smaller amounts of the alkalis (sodium and potassium oxides) and aluminium oxide. It was in the late 19th century, that German glassmaker Otto Schott first added Boric Acid to the traditional glass composition, creating the first batches of Borosilicate glass.
Borosilicate glass main property is that it does not expand like ordinary glass does. Due to its low coefficient of expansion, it has superior thermal shock resistance. This means that even if it undergoes a sudden temperature change it will not break. And in the very rare and extreme case that it did, it would only crack, not shatter. Borosilicate glass also has a higher melting point, making it more heat resistant than regular glass. It remains both clear and strong even when exposed to extremely high temperatures. It does not melt until 550 degrees Fahrenheit (287 C). High-end stage lighting, LED lights and stroboscopes are possible because of Borosilicate glass. Although the most common use for Borosilicate glass is for household ovens and cookware. This glass is also known for its extremely high chemical resistance, making it ideal for laboratory containers, test tubes ad beakers. Borosilicate glass handles even the most volatile chemicals, always remaining intact. It can even be used for nuclear waste storage.
Although temperatures required for the production of borosilicate are significantly higher than those used for regular glass making, it is still economic and relatively inexpensive to produce.
Borosilicate Glass is well-known for its durability, low coefficient of expansion, low density, high softening point, high resistance to acids and thermal shock, compared to other glass formulations. The chemical composition consists primarily of silicon oxide and boron oxide. Coefficient of thermal expansion for borosilicate glass is about one third of other glass compositions making it resistant to thermal shock, which is critical for those applications where minute deviations in shape might matter.
- Chemical Industry
- Pharmaceutical Industry
- Glass fibres for textile and plastic reinforcement