Dispersive Effects of the Stress-optic Response in Oxide Glasses

Abstract

Anisotropy in glass can lead to a transmitted double image due to birefringence. Stress-induced birefringence, the stress-optic effect, is undesirable for applications such as commercial imaging. The leading zero stress-optic glass exhibits dispersive effects near its absorbance edge and thus cannot be used in broadband applications. Finding zero stress-optic glasses with minimal dispersive effects over a broad band of the visible region requires a theory to predict which combinations of glass formers and modifiers could exhibit minimal dispersion.

Two glass families known to have a zero stress-optic response using white light, tin phosphates and tin silicates, were studied as a function of composition and wavelength. Near the absorbance edge, dispersion varied considerably with composition for tin phosphate glasses, but remained constant for tin silicate glasses. The significant factor is the oxygen bonding influence near the band edge. This leads to composition rules for synthesis of broadband, zero stress-optic glasses.