γ-Irradiation effects in borosilicate glass studied by EPR and UV-Vis spectroscopies

摘要

Assessing the behavior of borosilicate glass used for nuclear waste immobilization under irradiation is essential for determining the long-term behavior of the high-level waste. In this work, the y irradiation induced structural properties of the borosilicate glass have been studied via ultraviolet-visible (UV-Vis) spectroscopy and electron paramagnetic resonance (EPR) spectroscopy. The optical band gap (E_g) and the Urbach energy (E_u) deduced from the UV-Vis spectra of borosilicate glasses. The E_g decreased and the E_u increased with the increase of absorbed dose, which indicated the increase of non-bridging oxygen and disorder in the glass network. The EPR results revealed that there formed the following paramagnetic defects: hole center associated with boron (BOHC), hole centers near alkaline ions (HC_1 center), E' centers (≡Si·), peroxy radical (Oxy defect), non-bridging oxygen hole centers (NBOHC), BO_3~- center, Si - BOHC (≡B-O·-Si≡) and B-O-B-iso center (_(HO)~(HO)B~(HO) - O·~B_(HO)~(HO)).