Photoelastic studies of optically active crystals

7. Summary

Double refraction and optical activity are studied by employing the Rayleigh Compensator and the photoelastic constants of NaClO₃ have been redetermined, confirming the results obtained by Ramachandran and Chandrasekharan (1951). The photoelastic constants of NaBrO₃, another T-class crystal, have been determined for the first time, employing the Rayleigh Compensator and also the elliptic analyser previously employed by Ramachandran and Chandrasekharan for studying NaClO₃; and the results confirm the theoretical prediction of Bhagavantam (1942). The values for NaBrO₃ are as follows:p ₁₁=0·185;p ₁₂=0·218;p ₁₃=0·213;p ₄₄=−0·0139 andq ₁₁=1·63×10⁻¹³;q ₁₂=2·58×10⁻¹³;q ₁₃=2·45×10⁻¹³ q ₄₄=−0·93×10⁻¹³ (all in units of cm.² dyne⁻¹).