The effect of processing variables on structural changes and optical properties of SiO2-TiO2 sol-gel derived films

The structural evolution during the thermal treatment of 70SiO(2)-30TiO(2) (mole%) sol-gel derived powders and films was investigated by FT-IR, Raman and XPS, and XRD. From these results, the TiO2-rich regions involving Ti4ions in octahedral coordination were confirmed to be amorphous at 600 degre esC. However, Raman spectra a along with XRD patterns indicated that at hig h temperature (above 700 degreesC), the amorphous TiO2 was segregating to f orm anatase crystal. Also, the effect of experimental variables such as the rmal treatment, heating rate and exposure to water vapor on structural chan ges, refractive index and thickness of the film coated on soda-lime-silicat e glass were investigated.