DETERMINATION OF INTRINSIC CONSTANTS FOR THE KINETICS OF GROWTH AND DECAY OF FREE RADICALS IN ILLUMINATED KERATIN

Abstract— The growth and the decay of free radicals in illuminated keratin of five samples of wool have been studied by electron paramagnetic resonance. Illumination of the different samples varied from 10^-9 to 10^-7 Einstein cm^-2s^-1. The paramagnetic resonance spectra were measured both during illumination and during the decay of signals in the dark. The curves obtained during illumination gave two typical shapes: one approaching the apparent "saturation value", and the other passing through a maximum and then decreasing despite continuing illumination. All the above results are discussed in terms of only two prevalent free-radical species, whose growth and decay are determined for each species by a single intrinsic growth constant, and a single intrinsic decay constant. These four constants allow a reasonable fit for the complete behaviour of all five samples.