Proton-transfer lasers from solid polymeric chains with covalently bound 2-(2'-hydroxyphenyl) benzimidazole groups

The lasing properties of a number of newly synthesized 2-(2'-hydroxyphenyl) benzimidazole derivatives copolymerized with methyl methacrylate or dissolved in poly (methyl methacrylate) and pumped with an N(2) laser are reported. The radiation mechanism is based on the intramolecular proton-transfer in the electronic excited state. Both the lasing efficiency and the dye photostability increase significantly when the proton-transfer chromophore is covalently bound to the polymeric chain, and energy-conversion efficiencies comparable to those obtained in liquid solution are demonstrated.