Photo-responsive properties and heating-induced surface relief patterns from azobenzene-doped GeO₂/γ-glycidoxypropyltrimethoxysilane organic-inorganic hybrid films

GeO₂/γ-glycidoxypropyltrimethoxysilane organic-inorganic hybrid optical waveguide films, which contain azobenzene small molecular groups, have been prepared by combining a low temperature sol-gel process with a spin-coating technique. The azobenzene in hybrid films can undergo trans-cis-trans photoisomerization efficiently by a photoirradiation with UV light. It is also found interestingly that surface relief patterns can be heat-induced on such azobenzene-containing small molecular hybrid films, but can be erased by further heating the hybrid film and no permanent damage of the hybrid film is observed. The refractive index, thickness, and morphologic properties of the hybrid films have also been investigated by a prism coupling technique and atomic force microscopy. These results indicate that the azodye-doped hybrid films are promising candidates for integrated optics and photonic applications, which allow directly integrating on the same chip waveguide device with the optical data storage and optical switching devices.