International audienceP-related paramagnetic point defects were studied in irradiated Yb-doped phosphate glasses by electron paramagnetic resonance spectroscopy (X and Q-bands). A strong impact of the glass network type on the defect nature is shown. In all glasses, r-POHC defects formation is in strong correlation with Q(2) tetrahedra amount supporting the structure of r-POHC. Ultra-phosphate glasses contain the larger defect type: Peroxy radicals, P-1, P-2, and P-4 defects whose formation is linked to Q(3) tetrahedra presence. In meta-phosphate and poly-phosphate glasses, peroxy radicals appear with r-POHC thermal recovery. In meta-phosphate glasses, a combination of P-1 and P-3 defects was evidenced for the first time, whereas in poly-phosphate glasses, only P-3 defects were identified. Dose effect as well as defect recovery were analyzed. (C) 2014 AIP Publishing LLC

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Rare earth doped active glasses and fibers can be exposed to ionizing radiations in space and nuclear applications. In this work, we analyze the evolution of (2)F(5/2) excited state lifetime in Yb(3+) ions in irradiated aluminosilicate glasses by electrons and γ rays. It is found that the variation of lifetimes depends on the Yb(3+) clusters content of the glasses for irradiation doses in the 10(2)- 1.5∙10(9) Gy range. In particular, glasses with high clustering show a smaller decrease in lifetime with increasing radiation dose. This behavior is well correlated to the variation in paramagnetic defects concentration determined by electron paramagnetic resonance. This effect is also observed in Yb(3+) doped phosphate and Er(3+) doped aluminosilicate glasses, inferring that clustering plays an important role in irradiation induced quenching.