Spectroscopy of trivalent europium in gel-derived silica glasses

Luminescence spectra of Eu3+ in sol-gel-derived silica (SiO2) samples are reported and discussed as a function Eu3+ concentration and of heating. Lifetimes, linewidths and Stark splittings of the transitions are used for monitoring structure evolutions of the gel network; the data in the interval 25-250°C allow us to describe the general behaviour of the system during SiO, gel->txerogel transition.