Propriedades ópticas e estruturais dos vidros boratos puros e dopados com Nd2O3

• Ano de defesa: 2013
• Autor(a) principal: Sousa, Nuccia Carla Arruda de
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Alagoas; Brasil; Programa de Pós-Graduação em Física da Matéria Condensada; UFAL
• Palavras-chave em Português: Óptica; Matriz vítrea borato; Judd-Ofelt - Parâmetros; Efeito nefelauxético; Espectroscopia vibracional; Optical; Borate glass matrix; Nephelauxetic effect; Vibrational spectroscopy; CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA
• Link de acesso: http://www.repositorio.ufal.br/handle/riufal/1700

We investigated from the point of view of optical and vibrational the matrix 60B203 - (20 - x)Na2O - 10PbO - 10Al2O3 : xTiO2, with x= 0, 1, 2, 3, 4, e 5 mol% glasses, in order to understand the changes brought with the substitution of sodium oxide Na2O titanium oxide per TiO2. We performed measurements of X-ray diffraction, which revealed homogeneous amorphous structures throughout the composition range. The absorption spectra showed that the energy of the optical band gap (∆Eopt) and Urbach energy (UE) decreased with increased concentration of oxide TiO2. By using Vibrational Raman Spectroscopy and Fourier Transform Infrared (FTIR) spectroscopy, we have observed changes in the spectra, which indicated a relationship with the effect conversion BO4 to BO3 groups and the appearance of “loose” BO4, indicating that ions titanium acted as a modifier of the vitreous network. Subsequently, we investigated the effect of substitution of Na2O per TiO2 on the point of view of structural features and spectroscopic oxide dopant Nd2O3 the following borate glass matrix 60B2O3 - (20 - x)Na2O - 10PbO - 10Al2O3 : xTiO2 : yNd2O3. Were measured from X-ray patterns, temperatures glass (Tg), vibrational spectroscopy and Raman and Infrared measurements of optical absorption and emission spectra. The tendency of the glass transition temperature (Tg), Judd-Ofelt parameters, Ω(2;4;6) and the ratio for Nephelauxetic with increasing concentration TiO2 and Nd2O3 were interpreted quantitatively and qualitatively in terms of connections and coordination number. Measurements of glass transition temperature (Tg) for the entire series of glass system doped with neodymium ions (Nd3+) for different concentrations of titanium (Ti) suggested changes in the rigidity of the matrix due to the change coordinating boron oxide resulting from the effect of converting BO4 to BO3. The variation of the Judd-Ofelt parameters Ω 2 and Ω 4 indicated that the average radius of the rare earth-ligand decreased creating a distribution of electron density when the ion concentration of neodymium (Nd3+) increases.