Bulk and surface investigation of photooriented polymer films

The photo-generation of optical anisotropy is investigated in spin-coated f ilms of two liquid crystalline polymers containing differently substituted azobenzene side groups upon irradiation with linearly polarized light. UV s pectroscopy with polarized light. waveguide spectroscopy and NEXAFS (Near E dge X-ray Absorption Fine Structure) spectroscopy have been used to charact erize the photoinduced order within the film and at the surface. While azim uthal anisotropy is observed in the volume of both polymers. surface anisot ropy is only found in case of the homopolymer. The azobenzene moieties of t he copolymer do not show any out-of-plane orientation at the surface.