Raman spectroscopy study of β-irradiated silica glass

Natural and synthetic silica glass samples with different OH content have been submitted to P-irradiation at different doses from 106 to 5 x 10(9) Gy in a Van de Graaff accelerator. Structural changes under irradiation have been analyzed by Raman spectroscopy. The main findings are: (i) a decrease of the Si-O-Si angular dispersion and the average Si-O-Si angle as a function of dose and (ii) an increase of number of three-membered SiO4 ring concentration during irradiation. These results show therefore that purely electronic excitation from beta-irradiation induces in a-SiO2 small but significant structural changes of the SiO4 membered ring statistics (size and dispersion), consistent with a slight densification. (C) 2003 Elsevier B.V. All rights reserved.