Effect of spatial distribution of laser radiation intensity on photobleaching kinetics of dye in polymer matrix

The modeling of light-induced bleaching of eosin in polymer in the frame of four-level energy scheme $(S_0,S_1,T_1,T_n)$ was made taking the distribution of intensiviti in $TEM_{00}$ mode into account. It was shown that the time dependence of optical dentisty of the samples differs from the exponential relationship inherent for first order chemical reaction in the case of taking the normal intensity distribution into consideration. The conditions of experemental realization of correct definition kinetic paremeters of system were revealed.