Migration and segregation of sodium under β-irradiation in nuclear glasses

Raman,B-11 Nuclear Magnetic Resonance (NMR) and X-ray Photoelectron (XPS) spectroscopy investigations have been made on a series of beta-irradiated aluminoborosilicate glasses. This work shows the following changes of the glass structure under beta-irradiation: (i) an increase of glass polymerization, (ii) an increase of boron in a trigonal environment and (iii) no modification in the aluminum environment during irradiation. These glass modifications under beta-irradiation can be correlated with the migration of sodium outside of the Si and B glass network formers, Moreover, XPS experiments show a strong decrease of the sodium concentration at the surface of these irradiated glasses. This study presents therefore strong evidences of migration and segregation processes of sodium during a beta-irradiation in thr bulk for these simplified aluminoborosilicate glass compositions. (C) 2000 Elsevier Science B.V. All rights reserved.