Sorption and optical properties of sol-gel thin films measured by X-Ray Reflectometry and Ellipsometric Porosimetry

►The accessible porosity of sol-gel SiO2 and TiO2 films was determined. ►Porosity values decrease with thermal treatment. ►For sol-gel TiO2 films, wall refractive index increases with thermal treatment. ►For sol-gel SiO2 films, wall refractive index is constant with thermal treatment. ►Thermal treatment was optimized to obtain sol-gel thin films with very low porosity.