Spectroscopic photoelasticity of lead-silica glass analyzed by polarization modulated ellipsometry

Spectro-photoelasticity of lead-silica glass, in which the PbO content was varied from 71.1 wt% to 74.0 wt%, was investigated by polarization modulated ellipsometry, In contrast to quartz glass, which has a positive stress-optical coefficient throughout the wavelength region of 260 nm to 860 nm that is greater in the shorter wavelength region, the lead-silica glass showed the zero-point of the stress-optical coefficient which was shifted to a longer wavelength as the PbO content increased. Below the zero-point wavelength, the coefficient becomes negative, while above the zero-point wavelength the coefficient remains positive. As the PbO content increases, the refractive index of the lead-silica also increases indicating an increase of the lattice effect.