Glasses Tech

September 22, 2009

Dispersion of Thermooptic Coefficients of Soda-Lime-Silica Glasses

Filed under: Glasses 1995 — admin @ 5:28 am


The thermooptic coefficients, i.e., the variation of refractive index with temperature (dn/dT), are analyzed in a physically meaningful model for two series ofsoda-lime-silica glasses, 25Na//2O·xCaO·(75-x)SiO//2 and (25-x)Na//2O·xCaO·75SiO//2. This model is based on three physical parameters—the thermal expansioncoefficient and excitonic and isentropic optical bands that are in the vacuum ultraviolet region—instead of on consideration of the temperature coefficient ofelectronic polarizability, as suggested in 1960. This model is capable of predicting and analyzing the thermopotic coefficients throughout the transmission regiion of the optical glasses at any operating temperature.

Gorachand Ghosh

Glasses Tech