Ribeiro, S.J.L [UNESP]Dexpert-Ghys, JPiriou, BMastelaro, V.R2014-05-272014-05-271993-12-01Journal of Non-Crystalline Solids, v. 159, n. 3, p. 213-221, 1993.0022-3093http://hdl.handle.net/11449/64398The Raman, IR absorption and EXAFS spectra at the Ge K-edge and Pb LIII-edge of eight lead germanate glasses, with general formula xPbO(1-x)GeO2 with x = 0.20, 0.25, 0.33, 0.40, 0.50, 0.53, 0.56 and 0.60, have been measured. The occurrence of [GeO6] units besides [GeO4] could not be deduced unambiguously from the data. The vibrational and EXAFS data agree with a progressive depolymerization of the network. Starting from all Ge atoms linked to four bridging oxygens in GeO2 (x = 0), the number of tetrahedral units with one or two non-bridging oxygens increases with x. At low content, Pb2+ ions act as modifiers in the germanate structure, but to a lesser extent than an equivalent number of alkaline ions. © 1993.213-221engAtomsIonsLight absorptionMolecular structureOxygenAlkaline ionsBridging oxygenDepolymerizationLead germanate glassesNonbridging oxygensGlassArtigo10.1016/0022-3093(93)90225-MWOS:A1993LK25800003Acesso restrito2-s2.0-0027625227