A new method to probe the structural evolution during the heat treatment of SiO2–P2O5 gel glasses

Eu3+-doped SiO2–P2O5 gel glasses were prepared using sol–gel method. The structural evolution during the heat treatment of gel glasses was studied by DTA-TG, IR, XRD, as well as fluorescence spectra with Eu3+ as a probe. Results showed that hexagonal crystalline (5 SiO2·P2O5) appears in SiO2–P2O5 gel glasses when heated to 560°C. The structural variations of SiO2–P2O5 gel glasses can be correctly indicated by RI5D0→7F2/I5D0→7F1 curve of Eu3+ ion obtained from fluorescence spectra.