Light induced processes in thin films of indandione type organic molecules

The optically induced switching of material properties is important for investigations of opto-electronic effects and opto-mechanical properties. Investigated organic materials contain chromophore dipole consisting of acceptor and donor groups bridged by a delocalized π-electron system. Both calculations and experimental data show a reversible highly dipolar photoinduced intra molecular charge transfer in indandione type molecules (DMABI) accompanied by change of the sign and the value of the dipole moment. Investigations of optical properties of thin host-guest polymer films show that the photoinduced process of DMABI is related to the photoinduced switching between two equally stable states of the molecule. In this work first results of formation of the surface relief in polymer films incorporated with DMABI derivatives will be presented. The refractive index gratings of DMABI host-guest films show that red light is less diffracted than blue one. The reversible surface potential changes on irradiation in photoinduced intramolecular electron transfer band in polymer host-guest films is observed. The DMABI molecules in solid state have nonlinear optical properties, which can be used and investigated in host-guest polymer matrix. The influence of concentration of DMABI molecules on photoinduced processes is discussed.