Dynamic Solvent Effects in Photochromism of 2,2-Diphenyl-2H-1-benzopyran

Abstract

Pressure effects on the fading reaction of the title compound generated by UV irradiation were measured in ethanol and 2-methylpentane-2,4-diol (MPD). In ethanol, the reaction was accelerated with increasing pressures. In highly viscous MPD, however, viscosity induced retardation was observed at higher pressures. The dynamics of solvent reorganization will be discuss on the basis of pressure and viscosity effects of title compound compared with those of napthopyrans and 2,2-dimethylbenzopyran.