Laser photochemistry of poly(N-vinylcarbazole) in solution

The primary photoprocesses of N-vinylcarbazole oligomers and polymers excited with a pulsed intense laser were studied in solution. The triplet-triplet absorbance, fluorescence spectra, lifetime, intensity, and quenching efficiency show a distinct dependence upon excitation intensity and degree of polymerization. From these measurements it was concluded that several fluorescent states are produced in one polymer chain and their mutual interaction leads to efficient deactivation. One remaining fluorescent state is converted to the triplet state with a yield characteristic of the particular polymer. Some of these fluorescent chromophores are converted to the cation by a quenching reaction involving the electron acceptor, dimethyl terephthalate. This ionic photodissociation results in formation of a transient polyelectrolyte in organic solvents.