Speciation and polymerization in a barium silicate glass: evidence from 29Si NMR and Raman spectroscopies
| Autor: | Harold Lozano, Edgar Dutra Zanotto, Benjamin J.A. Moulton, Laís D. Silva, Paulo S. Pizani, Hellmut Eckert, Carsten Doerenkamp |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) Universidade de São Paulo (USP) instacron:USP |
| Popis: | Raman and NMR spectroscopies have long been employed in pursuing quantitative relationships between polymerization of silicate glasses and melts. However, varying assumptions and ambiguities have often meant structural models vary significantly depending on the probe used. This study investigates a 40BaO·60SiO2 glass to determine its polymerization using static and MAS 29Si NMR, and Raman spectroscopies to construct a coherent structural interpretation. The challenges and advantages of each technique are discussed as the structural model of 40BaO60SiO2 glass required partial evidence derived from each of these spectroscopies. The Raman scattering cross sections for Q2 and Q3 were found to be 0.85 and 1.22, respectively. The Qn distribution was shown to be 3, 35, 57, 6% (±4%) for Q1 to Q4, respectively. This distribution yields a polymerization consistent with the stoichiometry, Ba0.66SiO2.66, having a O:Si ratio of 2.66. The agreement between all Qn distributions, the stoichiometry, the polymerization, and equilibria strongly indicate that this structural interpretation is robust. |
| Databáze: | OpenAIRE |
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