Singlet oxygen and dye-triplet-state quenching in solid-state dye lasers consisting of Pyrromethene 567–doped poly(methyl methacrylate)

Solid-state dye lasers based on poly(methyl methacrylate) (PMMA) doped with Pyrromethene 567 dye (P567) have been investigated. The preparation techniques employed provided high photostability and laser damage threshold for P567 in pure PMMA with 270,000 pulses emitted before the conversion efficiency fell to half its initial value for a pump fluence of 0.16 J cm^-2. When PMMA was modified with 1,4-diazobicyclo [2,2,2] octane singlet oxygen quencher, the longevity increased to 550,000 pulses, corresponding to a normalized photostability of 270 GJ mol^-1. Modification of PMMA with a triplet quencher (perylene) yielded no improvement, but in ethanol solutions both additives enhanced photostability. It is possible that in PMMA, stabilization by means of triplet quenching that depends on dye diffusion is prevented but that stabilization by means of singlet oxygen quenching that depends on the faster oxygen diffusion rate will succeed.