Relations between photophysical and lasing properties of rhodamines in solid polymeric matrices

The photophysical properties of Rhodamine 6G derivatives with different substituents in the ester group, in solid solutions of copolymers of 2-hydroxyethyl methacrylate (HEMA) and methyl methacrylate (MMA) or covalently bound to the same polymeric chains, have been determined and compared with the lasing properties of the materials under irradiation with 337 nm (N-2 laser) pulses. In these solid media the rhodamine chromophore shows a photophysical behaviour similar to that in a liquid solution, and its photostability clearly increases when the chromophore is bound to the polymeric chain. These new solid materials show laser efficiencies that depend on the HEMA/MMA ratio, in some cases with values close to 20%.