Borosilicate glass (BSG) is a class of moderate-refractive-index glass comprised of silicon dioxide and boron oxide. Borosilicate glasses are known for having very low coefficients of thermal expansion, which makes them resistant to thermal shock. They are commonly used by chemists and chefs alike, who appreciate these forgiving mechanical properties.

Borosilicate glass’s optical properties (refractive indices, dispersion and Abbe number) are widely studied and published as these materials have been with us since the late 19th century. Its refractive index and density can be manipulated by incorporation of other elements. To say that this is an area of intensive study would not be an exaggeration. (BK7 is a particular kind of borosilicate glass that is discussed elsewhere in this database.)

For a typical sample of BSG the refractive index and extinction coefficient at 632.8 nm are 1.51446 and 0. Below are files of complete refractive index and extinction coefficients. If the file is not available for download, you can request our proprietary file by clicking "Request".

Refractive Index Reference - Filmetrics Composite

No guarantee of accuracy - use at your own risk.