Point defect stability in gamma irradiated aluminoborosilicate glasses: Influence of Yb ³⁺ doping ions

Yb-doped aluminoborosilicate were irradiated with gamma rays at 10 ⁴, 10 ⁵, 10 ⁶ and 10 ⁷ Gy. The thermal stability as well as the recovery at room temperature of paramagnetic point defects such as Boron Oxygen Hole Center (BOHC), peroxy radicals and E′ center were studied. At first, doping with Yb induced a saturation of the E′ defect production and more importantly, the E′ center recovering temperature was decreased by 50°C. E′ and BOHC defects both showed a limited stability at room temperature. By doping with Yb the glasses, the fading time of defects and in particular the BOHC defect recovery was modified. The BOHC defect showed moreover a larger sensitivity to photobleaching compared to the E′ centers.