XII Poster Session for Young Scientists, Do Ctoral and Full-Time Students

XII poster session for young scientists, do ctoral and full-time students

IIII-XX

ОПТИЧНИ СВОЙСТВА И СТРУКТУРА НА TiO2-BaO-V2O5 СТЪКЛА

OPTICAL PROPERTIES AND STRUCTURE OF TiO2-BaO-V2O5 GLASSES

T. Tasheva, V. Dimitrov

University of Chemical Technology and Metallurgy,

8, St. Kliment Okhridski Blvd., 1756 Sofia, Bulgaria

Glasses with composition xTiO2.(35-x)BaO.65V2O5 (x = 1, 3, 5, 10, 15 and 20 mol %) were prepared using a conventional melt quenching method. DTA and DSC analysis were performed. Theoretical refractive indices and optical band gaps of the glasses were calculated by Lorentz-Lorenz equation. The glasses were found to possess high refractive indices (2.38 – 2.58) and narrow band gaps (2.38 – 2.46 eV). The third order nonlinear optical susceptibility χ(3) was determined by generalized Miller's rule and three-photon model. The refractive index and the third order nonlinear optical susceptibility increased, while the band gap decreased with increasing TiO2 content. The average single bond strength BM-O and the interaction parameter A(n0) were determined. The bond strength was found to vary from 250 to 280 kJ/mol and A(n0) was in the 0.049 - 0.055 Å-3 range, thus suggesting the presence of weak chemical bonds. Such bonds, namely BaˑˑˑO=V and Ti-O-V were confirmed by the IR-spectra of the glasses. The high polarizability of oxide ions in these bonds accounts for the observed linear and nonlinear optical properties of the glasses. A structural model of glasses with high TiO2 content is proposed.

Key words: glass, refractive index, band gap, nonlinear refractive index, IR-spectra, chemical bonding

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