Effect of doping silica gel layers with TiOTi-Chains and Cu2+-ephedrine onthe sensitivity of the layers to gases

In this paper the interaction of polysiloxane and TiOTi-doped polysiloxane gel layers containing Cu2+-ephedrine (CuEP) with carbon dioxide, nitrogen a nd water is investigated. This interaction is studied through changes of th e output optical power from an optical fiber coated with the investigated g el layer. The layers are prepared with sols based on tetraethoxysilane and titanium isopropoxide, isopropanol, acetylacetone and Cu-2+-ephedrine by th e repeated dip-coating method. The applied gel layers are dried at 70 degre esC. Spectral and temporal changes of the output optical power due to effect of the tested gases are measured. The measurements show big changes of the out put optical power of fibers coated with CuEP-doped silica gel layers in a w avelength range from 400 to 700 nm, which is in relation with spectral effe cts of CuEP in alcoholic solutions. Relatively lower changes of the attenua tion spectra without any attenuation band are found in the spectra of TiOTi -doped siloxane gel layers containing CuEP. The angular distributions of th e output optical power of the coated fibers indicate high optical losses of the layers.