Luminescence studies in polymers—IV. Effect of orientation,tacticity and crystallinity on polystyrene and polyvinylcarbazole fluorescence

The fluorescence spectra of amorphous atactic, amorphous isotactic and crystallized isotactic polystyrene films have been compared. The effect of chain orientation has also been analysed on amorphous atactic samples. The results show that the fluorescence yield increases with crystallinity at room temperature and 77°K. The contribution of excimer fluorescence at 77°K increases according to the sequence: atactic < atactic oriented < isotactic amorphous < isotactic crystallized. An increase of the fluorescence yield with crystallinity was also observed for polyvinylcarbazole samples although the contribution of excimer fluorescence at 77°K is independent of crystallinity for this polymer. The results are interpreted in terms of energy migration.