Birefringence and Microstructure of Anisotropic Borosilicate Glasses

Optically anisotropic glasses were obtained by the uniaxial stretching of phase‐separated borosilicate glasses in the transformation temperature range. The sign inversion of the birefringence, induced by subsequent heat treatments, was correlated with microstructure. The positive birefringence is attributed to form birefringence and the negative birefringence to “distribution birefringence” caused by the anisotropic distribution of the separated phase. Copyright © 1976, Wiley Blackwell. All rights reserved