The kinetics of the thermal conversion of the cis to the trans isomeric forms of 1, 3- diphenyltriazene and 1-phenyltriazenes derived from cyclic amines were determined in both poly (methyl methacrylate) and polystyrene doped films in the glassy state, using UV–visible absorption spectroscopy. The kinetics of 1, 3-diphenyltriazene are well explained by a two- exponential function, whilst those of 1-phenyltriazene derivates fit a first-order rate law. In ...