Thermal Coefficient of Refractive Index of Optical Glasses*

The thermal coefficients of refractive index have been determined for 23 commercial glasses. The interferometric procedure consisted of determining both the change of optical path of each glass with a change of temperature at a given wavelength and set coefficient of linear thermal expansion of the glass for the same temperature range. A relationship for the dispersion of the thermal coefficient of the refractive index has been found. It has also been possible to relate the chemical composition of glass with the thermal coefficient of the refractive index.