Relations among nonbridging oxygen, optical properties, optical basicity, and color center formation in CaO-MgO aluminosilicate glasses
- Departamento de Fisica, Universidade Estadual de Maringa, Av. Colombo 5790, 87020-900, Maringa, PR (Brazil)
- Grupo de Espectroscopia Optica e Fototermica, Universidade Estadual de Mato Grosso do Sul-UEMS, C. P. 351, CEP 79804-970, Dourados, MS (Brazil)
- Laboratoire de Physico-Chimie des Materiaux Luminescents, Universite Claude Bernard Lyon 1, UMR 5620 CNRS, 69622, Villeurbanne (France)
In this study the relations among nonbridging oxygen (NBO), optical properties, optical basicity, and color center formation in CaO-MgO aluminosilicate glasses were studied. Samples containing (in mol %) 35.9-57.5 of CaO, 16-27.7 of Al{sub 2}O{sub 3}, 7.9-41.6 of SiO{sub 2}, and 6.5-6.9 of MgO were measured by optical absorption and excitation, luminescence, and Raman spectroscopy. The results showed that when the SiO{sub 2} content was increased, the absorption edge shifted toward lower wavelengths and the bonds between O{sup 2-} ions and cations became more covalent. These observations were confirmed by Raman results that showed a decrease in the number of NBO per silicon tetrahedron as a function of SiO{sub 2} content. The results indicate that the effects of higher NBO concentration are the narrowing of the band gap energy and the delocalization of O{sup 2-} electrons, which facilitates the O{sup 2-} electrons to be trapped by anion vacancies and, consequently, forming color centers. The relationship between color center formation and SiO{sub 2} content was confirmed by optical spectroscopic measurements under UV radiation.
- OSTI ID:
- 21185906
- Journal Information:
- Journal of Applied Physics, Vol. 104, Issue 9; Other Information: DOI: 10.1063/1.3010306; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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