Influence of SiO₂ on the structure and optical properties of lithium bismuth silicate glasses

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• 作者：Neetu Ahlawat ; Sujata Sanghi ; Ashish Agarwal ; Rajni Bala
• 关键词：Heavy-metal oxide glasses ; FTIR ; Optical material ; Glass network
• 刊名：Journal of Molecular Structure
• 出版年：2010
• 出版时间：15 January 2010
• 年：2010
• 卷：963
• 期：1
• 页码：82-86
• 全文大小：437 K

文摘

Bismuth silicate glasses containing lithium oxide with composition 20Li₂O·(80 − x)Bi₂O₃·xSiO₂ (5  x  70 mol % ) have been prepared by melt-quench technique. Density (D), molar volume (V_M) and glass transition temperature (T_g) for all the glass samples have been measured. FTIR spectroscopy has been employed to investigate the structure of these glasses in order to obtain information about the competitive role of Bi₂O₃ and SiO₂ in the formation of glass network. The increase of SiO₂ content in the glass matrix results in increasing the Si–O–Si bond angle and hence the ionicity of Si–O bond increases with decrease in Bi₂O₃/SiO₂ ratio. The optical transmittance spectra of all the glasses have been recorded in the wavelength range 200–3300 nm. The values of optical band gap (E_g) have been determined from the cutoff wavelength of these glasses. The average electronic polarizability of oxide ion () and the optical basicity (Λ_th) have been estimated from the calculated values of the E_g and were found to be dependent directly on Bi₂O₃/SiO₂ ratio. The variation in different physical parameters such as D, V_M and T_g and optical parameters; viz., E_g, , Λ_th with Bi₂O₃/SiO₂ ratio have been analyzed and discussed in terms of change in the glass structure.