Mixed network former effects in tellurite glass systems: Structure/property correlations in the system (Na2O)(1/3)[(2TeO(2))(x)(B2O3)(1) (- x)](2/3)

Autor(es)

Larink, Dirk ^[1] ; Eckert, Hellmut ^{[1, 2]}

Afiliação do(s) autor(es)

^[1] WWU Munster, Inst Phys Chem, D-48149 Munster - Germany

^[2] Univ Fed Sao Carlos, Inst Fis Sao Carlos, BR-13560970 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Non-Crystalline Solids; v. 426, p. 150-158, OCT 15 2015.
• Citações Web of Science: 5

Resumo

Mixed-network former effects upon glass transition temperatures, densities and electrical conductivities have been studied in glasses in the system (Na2O)(1/3){[}(2TeO(2))(x)(B2O3)(1) (-) (x)](2/3). Mixing of network formers B2O3 and TeO2 has a negative effect on ionic conductivities. Possible structural origins of this behavior have been studied by B-11, Na-23, and Te-125 high-resolution and dipolar solid state nuclear magnetic resonance (NMR) techniques, O-1s X-ray photoelectron spectroscopy and Raman spectroscopy. A quantitative structural model has been developed that is consistent with all of the experimental data, and provides a detailed description of network modification processes, interactions and connectivities. All the O-1s XP spectra can be satisfactorily fitted with two line shape components with the parameters of the binary end-member glasses, providing no evidence for the possible formation of B-O-Te linkages. In addition, none of the Te-125 and B-11 NMR data shows significant proof of such linkages, even though their formation cannot be explicitly excluded. Na-23 NMR data indicate a monotonic chemical shift trend consistent with proportional sharing of the network modifier between the two network former species. The experimental data suggest a tendency towards an avoidance of B-O-Te linkages, even though no macroscopic phase separation is observed. Nevertheless, the negative mixed network former effect can be rationalized in terms of compositionally segregated sodium borate and sodium tellurite nano-domains. (C) 2015 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 13/07793-6 - CEPIV - Centro de Ensino, Pesquisa e Inovação em Vidros
• Beneficiário: Edgar Dutra Zanotto
• Linha de fomento: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs