Photodegradation of Coumarin Laser Dyes. An Unexpected Singlet Self-Quenching Mechanism

摘要

Photolysis of aminocoumarine laser dyes, including 7-diethylamino-4-methyl-coumarin has been investigated. Dealkylation of groups at the 7-dialkylamino functionality, reduction of the lactone moiety and overall photodecomposition of dyes have been observed. Concentration quenching of dye fluorescence is important at concentrations above 0.01 M. The photolysis is ascribed to singlet self quenching; triplet states are formed in low yield (flash photolysis) and are not reactive. (Author)