Luminescence studies in polymers—II : Temperature effect on polyvinylcarbazole fluorescence

Polyvinylcarbazole (PVCa) films and solutions emit normal and excimer fluorescence between 77 and 425 K. The absolute (I_M and I_D) and relative (I_M/I_D) intensities emitted strongly depend on temperature. The usual U-shaped curve is obtained for log I_M/I_D as a function of 1/T in the case of polymer films. In solution, two minima corresponding to two different excimers are observed. The formation and dissociation of PVCa excimers in films and solutions have been interpreted according to the usual kinetic scheme. The binding energies for the excimer in films and for the high temperature excimer in solutions are respectively 4 and 2·8 kcal mole⁻¹.