Photoselection of di-p-anisylnitroxl in glassy matrices

A photochemical reaction of a di-p-anisylnitroxyl radical destruction is in vestigated. Di-p-anisylnitroxyl irradiated by light at 436 and 365 nm is sh own to undergo decomposition both in liquid solutions and solid low-molecul ar and polymeric matrices. The quantum yield of the photochemical reaction ranges from 10(-4) to 10(-2), depending on the matrix, temperature, and rad iation wave length. The product of the photochemical transformation is tent atively identified as an R-(N)over dot-O-R aminyl radical. In samples photo lyzed by polarized light light-induced linear optical dichroism and angular dependence of EPR spectra are observed which arise as a result of photosel ection. The principal values of the absorptivity tensor and direction of th e dipole moment of the optical transition responsible for the photochemical reaction are determined. The kinetics of di-p-anisylnitroxyl photolysis in solid matrices is complicated by the kinetic non-equivalence phenomenon. T he kinetics of the photochemical reaction proceeding with photoselection is satisfactorily described by theoretical calculations. It is inferred that di-p-anisylnitroxyl can be used as a probe for investigating molecular mobi lity by relaxation of light-induced anisotropy.