Photostability of some pyrromethene laser dyes

Using flashlamp excitation, photostability data on 1,3,5,7,8-pentamethyl-, 1,2,3,5 6 dipropyl-1,3,5,7,8-pentamethyl-, and 2,6-dinitro-1,3,5,7,8-pentamethyl-pentamethyl-pyrromethane- (P)-BF2 complexes in the solvent 1,4-dioxane and the solvent mixtures 1,4-dioxane/heptane, 1,4-dioxane/cyclohexane, 1,4-dioxane/ethanol and 1,4-dioxane/hexanol, all ratio 1:4, were obtained. As reference laser dyes, the photostability of Rhodamine 6G in ethanol and the solvent mixture ethanol/hexanol ratio 1:4 and Rhodamine 560 in ethanol and the solvent mixtures ethanol/hexanol, ethanol/cyclohexane, and ethanol/heptane, all ratio, 1:4 were also obtained. Specifically, the laser output energy, Delta E (in joules) was recorded as a function of flashlamp excitation pulses, N. 2,6-dinitro-pentamethyl-P-BF2 was very stable in the heptane mixture, and other P-BF2 complexes were mom stable in 1,4-dioxane. Rhodamine 6G was very stable photo chemically in hexanol. The role of oxygen in laser dye solutions is briefly reviewed.