Influence of the host structure and doping precursors on rare earth clustering in phosphate glasses analysed by co-operative luminescence

Co-operative luminescence has been observed in ytterbium doped MgO-Li2O-P2O5 phosphate glasses. The intensity of this emission, which is correlated to the degree of Yb3+ clustering in the glass, increases with increasing ratio R between network modifiers and the network former. An abrupt change occurs around the metaphosphate composition (R = 1). These results can be explained by the evolution of the phosphate glass structure. Yb3+ clustering is reduced in samples synthesized with YbP3O9 doping precursor, instead of the usual Yb2O3 precursor. The effect is more pronounced for high R glasses. (C) 2000 Elsevier Science B.V. All rights reserved.