Borosilicate glass was first developed by German glassmaker Otto Schott in the late 19th century in Jena. This early borosilicate glassware 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  Borosilicate glass is the name of a glass family with various members tailored to completely different purposes.

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 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. Also in cookware, lighting, and in certain kinds of windows.

The manufacturing process depends on the product geometry and can be differentiated between different methods like floating, tube drawing, or molding.


The common type of borosilicate glass used for laboratory glassware has a very low thermal expansion coefficient about one-third that of ordinary soda-lime glass. This reduces material stresses caused by temperature gradients, which makes borosilicate a more suitable type of glass for certain applications. Fused quartzware is even better in this respect (having one-fifteenth the thermal expansion of soda-lime glass); however, the difficulty of working with fused quartz makes quartzware much more expensive, and borosilicate glass is a low-cost compromise. While more resistant to thermal shock than other types of glass, borosilicate glass can still crack or shatter when subjected to rapid or uneven temperature variations.





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