Laser spectroscopy and electron paramagnetic resonance of Cr3+ doped silicate glasses

• Published in: Journal of non-crystalline solids 2000-08, Vol.273 (1-3), p.209-214
• Main Authors: COSTA, V. C, LAMEIRAS, F. S, PINHEIRO, M. V. B, SOUSA, D. F, NUNES, L. A. O, SHEN, Y. R, BRAY, K. L
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity); Optical constants: refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Other solid inorganic materials; Photoluminescence; Physics
• ISSN: 0022-3093
• DOI: 10.1016/S0022-3093(00)00170-8

Gels and glasses in the SiO2-Al2O3-ZnO-Cr2O3 and SiO2-Al2O3-MgO-Cr2O3 systems were synthesized by the sol-gel method. A description of the change of the Cr3+ environment during the xerogel-glass-glass ceramic transformation is presented using optical properties of Cr3+ ions. Absorption and emission spectra, EPR measurements, and site-selective laser spectroscopy were performed to characterize the Cr3+ fluorescent centers. Absorption and fluorescence are interpreted by structural considerations showing the variation of Cr3+ environment during heat treatment. By heating glasses, the glass-ceramics containing Cr-doped ZnAl2O4 (gahnite) are formed. The results indicate the presence of Cr ions in a gahnite crystalline phase and emission from the 2E level is observed. Also a Cr3+ fluorescence centered at 770 nm results from 4T2 level of Cr3+ sites at low ligand field in glassy phase. 25 refs.