Photoisomerization and thermoisomerization. III: tert-butyl method of selective preparation of photochromic crystalline salicylideneanilines and elucidation of substituent effects on the kinetics of the colour-change process

Abstract Salicylideneanilines possessing tert -butyl and other groups as ring substituents were synthesized and their photochemical properties were studied. The introduction of the bulky- tert -butyl substituent enabled photochromic Schiff base crystals to be prepared. Substituent effects on the photochromic phenomenon were determined by the kinetic measurement of the thermal bleaching reaction of the photocoloured species.