Credit: Nilanjana Shasmal - CeRTEV
Recent findings from the Center for Research, Education and Innovation in Vitreous Materials (CeRTEV) in São Paulo, Brazil have shown that the addition of niobium oxide in silicate glass increases bond density. The increase in bond density and the resulting increase in connectivity provide enhanced thermal and mechanical stability in specialty glass products.
The study, published in Acta Materialia, utilized Raman spectroscopy as well as nuclear magnetic resonance spectroscopy to analyze specialty glass products. “Our study combined experimental observations using nuclear magnetic resonance spectroscopy and Raman spectroscopy with computational modeling,” said Henrik Bradtmüller a postdoctoral researcher at the Federal University of São Carlos’s Center for Exact Sciences and Technology (CCET-UFSCar). “Besides the results mentioned, we found that higher levels of niobium led to Nb2O5, clustering, and heightened electronic polarizability, with a significant impact on the optical properties of the glass,”
Despite wide applications in specialty glass thanks to its non-linear optical properties, the role of niobium was largely not understood until now. “We discovered through spectroscopy that the addition of Nb causes ‘polymerization’ of the silica-oxygen network, increasing the connectivity of the glass’s components. This clarified the role of Nb as a ‘network former’,” said Bradtmüller.
The researchers utilized computational modeling that showed niobium tends to form clusters at higher Nb2O5 concentrations, while lithium ions are randomly distributed at the nanometric scale. This structural arrangement has never before been demonstrated in specialty glass.
“In a broader perspective, the study points to an experimental and computational strategy to investigate the role played in glass by intermediate oxides with active nuclei for NMR spectroscopy,” said Edgar Dutra Zanotto, director of CeRTEV.