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

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
silicamaterials at room temperature is calculated from increase
of the intensity of Sm3? f–f absorption transitions during time.