Vitreous optical constants

Fig. 3.4-29 Measured optical constants n(X) and k(X) of vitreous silica according to [4.16]...

Most of the other properties of vitreous silica are only slightly affected by the hydroxyl concentration. While it is possible to measure the effect of hydroxyl content on the density, refractive index, thermal expansion coefficient, dielectric constant, and other properties of vitreous silica, the effects are very small as compared to those for the flow and optical transmission behavior. The density of commercial vitreous silica ranges from 2.197 to 2.203 gcm while the refractive index is 1.457 0.003 for most products. Since the effects of hydroxyl on the properties of vitreous silica are of the same magnitude as the effects of changes in fictive temperature, it is very difficult to separate the effect of hydroxyl from those of thermal history. 

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