The Effects of the Polarisation of the Constituent Ions on the Photoelastic Birefringence of the Glass

JSGT 1956 V40 T353-T362

The effects of the properties of constituent ions on the photoelastic birefringence of simple glasses were studied by adding alkali oxides and fluorides, alkaline earth oxides and fluorides, and other metal oxides to lead silicate and lead phosphate glasses. This study proves the postulate of W. A. Weyl that the birefringence of a stressed glass is the result of the mutual polarisation of all anions and cations. The sign and the magnitude of the photoelastic birefringence of a glass are the result of two antagonistic effects: (1) an effect as the result of the deformation of polarisable anions, and (2) a counter-effect resulting from the deformation of the polarisable' cations. The former makes the birefringence positive, and the latter, negative.

Megumi Tashiro