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 N2 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.