PHOTOINDUCED MOLECULAR-REORIENTATION IN POLYMERS, LANGMUIR-BLODGETT-FILMS AND LIQUID-CRYSTALS

A review of the experimental data on a photoinduced molecular reorient ation in various molecular guest-host systems (dyes in liquid solution s, liquid crystals and polymer matrices), side-chain polymers and Lang muir-Blodgett films (LBFs) containing light absorbing chromophores is presented. The photoorientation may be reversible or irreversible. It is accompanied by the photoinduced dichroism and optical anisotropy wh ich is widely used for optical recording information. Special attentio n is paid to the photoassisted poling of polymers and LBFs, a novel te chnique that allows for the preparation of the stable photoelectrets a t room temperature possessing very promising nonlinear optical propert ies. The physical mechanisms of the photoinduced molecular reorientati on are discussed.