A comprehensive kinetic, thermodynamic and photochemical study of some spiro-indoline-oxazines

Abstract

The thermoreversible photochromic reaction of spiro-indoline-oxazines to photo-merocyanines has been studied by stationary spectrophotometric techniques. Two methods are described for determining the molar absorption coefficient of the metastable photomerocyanine and the quantum yield of the colour-forming photoreaction. Kinetic parameters (reaction rate and activation energy) and thermodynamic quantities (equilibrium constant and enthalpy) of the thermal reaction have also been determined. Based on the results obtained, some general correlations between the structure of these molecules and their photochromic and thermochromic properties have been drawn. © 1995 Indian Academy of Sciences.