Synthesis and properties of multicomponent lead fluoroborate glasses containing rare earth ions

A new multicomponent oxyfluoride glasses in PbO - PbF2 - B2O3 - Al2O3 - WO3 - Ln(2)O(3) system (where Ln = Pr, Nd, Eu, Tm, Er) were prepared. Lead oxide was partially or totally substituted by lead fluoride in oxide matrices, where the weight ratio of the lead to the boron atom is changed from 1:4 to 4:1. However, only several transparent glass samples with the Pb : B ratio from 1 : 2 to 4 : 1 have been obtained. The (PbO+PbF2)/B2O3 compositional dependence on the existence of the berate species was also supported by Raman spectroscopy. The strong peak at about 805 cm(-1) due to the totally symmetric vibration identified as trigonal deformation of the boroxol ring has been observed for samples with the Pb : B ratio equal to 1 : 2, whereas coexistence of both BO3 and BO4 units is evident with increasing of total (PbO+PbF2) lead concentration.