Abstract

Polyaniline (PAn) and derivatives have been again the subject of great interest owning to the larger nonlinearity, easy fabrication and its excellent stability under ambient condition in comparison with other families of conducting polymer. Photoinduced absorption and bleaching in PAn have been observed and attributed to the existence of localized molecular excitons and polaron pairs.^[1,2] For nonlinear optical device applications, the dynamics of the nonlinearity response is the important aspect of the polymer properties which in PAn and derivatives, however, has not been investigated intensively. In this paper we report femtosecond absorption saturation studies on exciton dynamics in PAn and polyaniline-polyraethyl mathacrylate (PAn-PMMA) blend films for the first time. Time-resolved absorption traces show significant different excitonic dynamics in these two polymers. In PAn a initial ultra­fast absorption saturation recovery is observed. In PAn-PMMA pump-probe trace shows an efficient two-photon absorption. We present a brief discussion on these ultrafast phenomena and predict their potential applications in optics.

© 1994 Optical Society of America