Dual Fluorescence of N-Pyrrolobenzonitrile in Extended Polyvinyl Alcohol Films

摘要

The possibility of radically changing the conditions for charge transfer (CT) photoreaction in N-pyrrolobenzonitrile molecules in polymer matrices of polyvinyl alcohol (PVA) under their extension has been demonstrated. The fluorescence spectrum of N-pyrrolobenzonitrile in PVA has two characteristic bands in the UV and visible spectral ranges, which are indicative of the CT reaction that occurs in the excited state. Extension significantly reduces the intensity of the UV band, the contribution of which in unstrained samples is comparable with the violet fluorescence intensity. Even a single extension of PVA films significantly reduces the intensity of the UV band, while a sixfold extension dramatically enhances this effect. In the latter case, the fluorescence spectrum contains a strong CT band whose relative intensity exceeds that for highly polar aprotic solvent acetonitrile by a factor of five. The data obtained indicate that, using extension, one can change the main intermolecular factors affecting the CT rate in PVA samples.