Influence of external β-irradiation in oxide glasses

Radiation effects in oxide glass as external β-irradiation has been investigated by Raman spectroscopy, Cr³⁺ luminescence and EPR spectroscopy to analyze microstructure evolution. Comparison between simplified and complex glasses (high-level nuclear waste glass analogue) was undertaken. Migration and segregation of sodium have been confirmed on simplified irradiated glasses by a polymerization increase and dissolved oxygen presence. Densification under irradiation has also been demonstrated with the increase of three-membered silicate rings in silicate glass and the decrease of the average Si-O-Si angle in the borosilicate glass. In both glasses, Cr³⁺ crystal field was increased, suggesting a Cr-O length decrease. The complex borosilicate glass responds differently: densification effect and Na segregation were not detected. Under β-irradiation, electron-trapping processes on Cr⁶⁺ occurred, forming Cr⁴⁺ and Cr⁵⁺ species.