We report picosecond photoinduced bleaching (PB) of the exciton absorption of the emeraldine base form of polyaniline. The temperature- (T-) independent dispersive decay, ∼$t^{\mathrm{-}0.11}$, observed in this study differs markedly from the dynamics of earlier studied semiconductors. It also contrasts with long-time PB, which varies as $t^{\mathrm{-}\beta }$ with β∼0.5, and is weakly T dependent. These results point to the likely role of rotations in ring-containing polymers.

• Received 20 April 1989

DOI:https://doi.org/10.1103/PhysRevB.40.4187