Correlation between structure and optical properties of lead metasilicate glass-ceramic under high hydrostatic pressures

• Ano de defesa: 2022
• Autor(a) principal: Pena, Rafaella Bartz
• Orientador(a): Pizani, Paulo Sergio
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de São Carlos; Câmpus São Carlos
• Programa de Pós-Graduação: Programa de Pós-Graduação em Física - PPGF
• Palavras-chave em Português: Vidro Metasilicato de Chumbo; Altas pressões; Cristalização total; Espectroscopia Raman; Fotoluminescência
• Palavras-chave em Inglês: Lead Metasilicate Glass; High-Pressure; Overall Crystallization; Raman Spectroscopy; Photoluminescence
• Área do conhecimento CNPq: CIENCIAS EXATAS E DA TERRA::FISICA; CIENCIAS EXATAS E DA TERRA::FISICA::FISICA DA MATERIA CONDENSADA::PROP.OTICAS E ESPECTROSC.DA MAT.CONDENS;OUTRAS INTER.DA MAT.COM RAD.E PART.
• Link de acesso: https://repositorio.ufscar.br/handle/20.500.14289/17150

Glass structures are determined by not only composition, pressure, and temperature but also by the pressure and thermal histories in which the glass was submitted. In this thesis, a systematic study of these variables was performed in undoped and cobalt-doped lead metasilicate (PbSiO3) glasses and mainly probed by Raman spectroscopy. High pressure was applied in a Diamond Anvil Cell (DAC), and the samples were studied ex-situ and in-situ. Ex-situ Raman investigation appoints for an unusual increase in the non-bridging oxygens (NBO) population, at the expense of the bridging oxygens (BO) population, leading to slight depolymerization of the densified metasilicate structure. In-situ investigation of this glass under pressure suggests the densification mechanisms occurring via the formation of an intermediary more polymerized state. Such modifications are accompanied by a change in the lead environment with the formation of highly coordinated PbOn polyhedra. High-temperature investigations were performed in isothermal and non-isothermal runs, providing evidence that the phase evolution from the glass to the stable alamosite is intermediated by two metastable crystalline phases, with a temperature-dependent crystallization path. For the same composition submitted to extremal conditions, the controlling of these structures may offer vast possibilities to tailor the glass-ceramic optical properties.