Borosilicate glass is a type of glass with silica and boron trioxide as the main glass-forming constituents. Borosilicate glasses are known for having very low coefficients of thermal expansion (≈3 × 10−6 K−1 at 20 °C), making them more resistant to thermal shock than any other common glass. Such glass is subjected to less thermal stress and can withstand temperature differentials without fracturing of about . It is commonly used for the construction of reagent bottles and flasks as well as lighting, electronics, and cookware. Borosilicate glass is sold under various trade names, including Borosil, Duran, Pyrex, Glassco, Supertek, Suprax, Simax, Bellco, Marinex (Brazil), BSA 60, BSC 51 (by NIPRO), Heatex, Endural, Schott, Refmex, Kimax, Gemstone Well, and MG (India). Single ended self-starting lamps are insulated with a mica disc and contained in a borosilicate glass gas discharge tube (arc tube) and a metal cap. They include the sodium-vapor lamp that is commonly used in street lighting. Borosilicate glass melts at about . History Borosilicate glass was first developed by German glassmaker Otto Schott in the late 19th century in Jena. This early borosilicate glass thus came to be known as Jena glass. After Corning Glass Works introduced Pyrex in 1915, the name became synonymous for borosilicate glass in the English-speaking world (since the 1940s, a sizable portion of glass produced under the Pyrex brand has also been made of soda-lime glass ). Borosilicate glass is the name of a glass family with various members tailored to completely different purposes. Most common today is borosilicate 3.3 or 5.0x glass such as Duran, Corning33, Corning51-V (clear), Corning51-L (amber), International Cookware's NIPRO BSA 60, and BSC 51. Manufacturing process Borosilicate glass is created by combining and melting boric oxide, silica sand, soda ash, and alumina. Since borosilicate glass melts at a higher temperature than ordinary silicate glass, some new techniques were required for industrial production. In addition to quartz, sodium carbonate, and aluminium 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 or potassium oxide and 2–3% aluminium oxide. Though more difficult to make than traditional glass due to its high melting temperature, it is economical to produce. Its superior durability, chemical and heat resistance finds use in chemical laboratory equipment, cookware, lighting, and