Photoinduced three-dimensional structures in amorphous and LC polymers
The 3D anisotropy generated by photoorientation of thin films of azobenzene containing polymers can be determined using waveguide spectroscopy. Irradiation of the films in the glassy state of the polymers with polarized light resulted in almost perfectly oblate index ellipsoids. Recently, we have found, that in the case of LC polymers the anisotropy can be amplified by annealing. The investigation of a number of polymers shows, that various types of 3D orientations (biaxial and uniaxial, oblate and homeotropic) can be obtained by such a annealing procedure. The film interfaces seem to play a crucial role for the respective behaviour.