Effect of Doping Silica Gel Layers with TiOTi-Chains and Cu2+-Ephedrine on the 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 and water is investigated. This interaction is studied through changes of the output optical power from an optical fiber coated with the investigated gel layer. The layers are prepared with sols based on tetraethoxysilane and titanium isopropoxide, isopropanol, acetylacetone and Cu²⁺-ephedrine by the repeated dip-coating method. The applied gel layers are dried at 70°C.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 output optical power of fibers coated with CuEP-doped silica gel layers in a wavelength range from 400 to 700 nm, which is in relation with spectral effects of CuEP in alcoholic solutions. Relatively lower changes of the attenuation spectra without any attenuation band are found in the spectra of TiOTi-doped siloxane gel layers containing CuEP. The angular distributions of the output optical power of the coated fibers indicate high optical losses of the layers.