Time evolution of samarium doped silica sol–gel materials followed by optical spectroscopy

Abstract

Sol–gel preparation conditions and optical spectra between 220 and 900 nm of Sm³⁺ doped silica materials are discussed. It is demonstrated that the intensity of the O²⁻ → Sm³⁺ charge transfer transition at 285 nm depends on gelation conditions due to samarium related defects in the silica matrix. The room temperature sol–gel transformation and drying of Sm³⁺ doped samples is followed using UV/Vis spectroscopy. The rate of densification of samarium doped silica materials at room temperature is calculated from increase of the intensity of Sm³⁺ f–f absorption transitions during time.