DUAL FLUORESCENCE OF ESTER DERIVATIVES OF DIALKYLANILINE IN POLYMER MATRICES - A TIME-RESOLVED FLUORESCENCE STUDY USING PICOSECOND DYE-LASER PULSES AS EXCITATION SOURCE

Using time-resolved fluorescence (TRF) measurements, it is shown that, for p-N,N-dimethylamino-benzoic acid ethylester (DMABEE) and p-N,N-diethylamino-benzoic acid ethylester (DEABEE) in polymethacrylate (poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA), poly(butyl methacrylate) (PBMA) and poly(hexyl methacrylate) (PHMA) matrices, the rate of formation and lifetime of the twisted intramolecular charge transfer (TICT) state are determined by the opposing roles of the polarity and the free volume of the polymer sites. The TRF spectra increase with increasing time after excitation, and the most intense spectra are observed in PHMA, which is the least polar and least viscous in this series of polymers. The role of the angle of pretwist of the donor substituent in TICT state formation is confirmed.