Photostability studies of thermomesomorphic derivatives of 2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione

In this study, the photophysical characteristics, like molar extinction coefficients, Stoke's shifts, quantum yields, radiative and fluorescence lifetimes, fluorescence rate constants, radiationless deactivation rate constants, and singlet energies of the fluorescent mesomorphic diketopyrrolopyrrole derivatives, (DPPDs), 3,6-bis(4-octyloxyphenyl)-2,5dihydro-2,5-dimethylpyrrolo[3,4-c]pyrrole-1,4-dione (DPPD-1) and 3,6-bis(4'-butylbiphenyl-4-yl)-2,5-dihydro-2,5dimethylpyrrolo[3,4-c]pyrrole-1,4-dione (DPPD-2) have been determined. The photostability studies were carried out under xenon arc lamp, direct and concentrated sunlight in solution of chloroform and tetrahydrofuran as well as in solid state, embedded in matrices of polyvinyl chloride (PVC) and sol-gel. The studies reveal that the photostabilities of the DPPD derivatives in PVC and sol-gel matrices are enhanced compared to solutions of chloroform and tetrahydrofuran. (C) 2003 Elsevier Ltd. All rights reserved.