A straightforward method of analysis of first-order processes with distributed parameters

A method has been put forward allowing direct determination of parameters describing the kinetics of first-order processes controlled by distributions of rate constants. The method consists in examining the time dependence of the (concentration×time) product: the maximum of the resulting function is directly related to the time constant of the kinetic process, and its width to the width of the distribution of the activation energies. The method has been applied to interpret the kinetics of bleaching reactions in solutions of photochromic polymers containing spiropyrane moieties attached to the poly(methyl methacrylate chain).