TRIPLET-TRIPLET ANNIHILATION IN MICELLES INCLUDING TRIPLET INTERMICELLAR MIGRATION

The problem of triplet-triplet annihilation in micelles is analyzed un der conditions where triplet molecules are mobile species migrating be tween micellar confinements. Using a stochastic treatment, it is demon strated that the tripler decay is characterized by a faster component due to the intramicellar annihilation followed by a slow component asc ribed to the intermicellar migration and self-decay of the triplets. T he slow process can be properly fitted by a decay function resulting f rom a competition of second-order and first-order processes of the cla ssical chemical kinetics. The method is extended to experimental data obtained from laser flash photolysis of safranine in sodium dodecyl su lfate (SDS) solution. Analysis of triplet decays of the monoprotonated safranine at several different dye concentrations in 10 mM SDS, pH = 10 and ionic strength 0.1, yields a triplet mean residence time of abo ut 10.4 +/- 2.7 mu s. The tripler decay time of the dye in these exper imental conditions is 23.4 +/- 2.2 mu s.