Luminescence quenching by iron in calcium aluminoborate glasses

The effects of iron content and of composition on the boron oxygen hole center (BOHC) in calcium aluminoborate glasses gamma-irradiated with 10(7) R have been analyzed by thermoluminescence (TL), electron paramagnetic resonance (EPR), optical absorption and Mossbauer spectroscopy, It was observed that the Fe2+ in tetrahedral coordination inhibits the formation of the boron oxygen hole center during the irradiation through the capture of a hole resulting in quenching of the thermoluminescence observed between 350 and 670 K. These results are different from the thermoluminescence quenching observed at low temperature [S.M. Del Nery, W.M. Pontuschka, S. Isotani, C.G. Rouse, Phys. Rev. B 49 (1994) 3760] that was attributed to non-radiative recombinations. (C) 1999 Elsevier Science B.V. All rights reserved.