It was apparently first sold under the name "Duran" in Europe in 1893. In the United States, "Pyrex" became synonymous with borosilicate glass after Corning Glass Works inventor Mr. Joe Littleton introduced it to the English speaking world in 1915.
Physical Characteristics
While manufacture of borosilicate glass Boron is added to a much purer type of silica sand. The composition of borosilicate glass is generally about 80% silica, 10% boron oxide, 8% sodium oxide, 8% potassium oxide, and 1% aluminum oxide.
Borosilicate glass used in lab ware has a very low thermal expansion coefficient (32.5-33), which is about 1/3 that of "soft" glass. This reduces material stress caused by changes in temperature, and hence the glass is more resistant to breakage. It is NOT invincible, though -- it will break or crack if dropped or otherwise impacted. Fortunately, it is much more likely to crack or snap rather than to shatter. It has a softening point (at which the glass may slump under its own weight) of 800°C is where glass blowers normally work it. The annealing point (the temperature at which residual strain or stress will relieve itself) at around 560°C.
Under "normal" laboratory conditions, borosilicate glass can withstand extended temperatures of around 230-240°C. For very short-term use, it will generally survive temperatures around 400°C. But the absolute maximum operating temperature for the formed glass is 450°C. Temperature changes from very hot to very cold should be also be avoided -- a maximum thermal shock differential of 160°C should be observed.
Borosilicate glass is very resistant to chemical corrosion, which makes it perfect for laboratory use. It can handle extremely volatile chemicals, and even nuclear waste! Everything has an Achilles heal and for borosilicate glass, it is fluorine’s. Hydrofluoric acid can only etch borosilicate glass.
