Analysis of photoelastic behaviour of fluorite-structure crystals

An analysis of the photoelastic behaviour of fluorite-structure crystals is performed by considering the existing theories of electronic polarizabilities of ions. On the basis of experimental and theoretical information available for electronic polarizabilities it is assumed that the change in polarizibility due to strain under the effect of hydrostatic pressure is mainly arising from the change in anion polarizability. Values of strain polarizability parameters and volume derivatives of refractive index or electronic dielectric constant are evaluated and compared with experimental data for CaF2, SrF2, BaF2, PbF2, Sr(NO3)2, and Pb(NO3)2 crystals. (author)