Murugan, G Senthil and Varma, KBR (2001) Dielectric, linear and non-linear optical properties of lithium borate±bismuth tungstate glasses and glass-ceramics. In: Journal of Non-Crystalline Solids, 279 (1). pp. 1-13.
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Glasses of various compositions in the system (1 - x) Li2B4O7 - xBi(2)WO(6) (0 less than or equal to x less than or equal to 0.35) were prepared via a melt-quenching technique. The amorphous nature of all the compositions of the as-quenched glasses under study was confirmed by X-ray powder diffraction (XRD) studies. The glassy nature of the as-quenched glasses was established by differential thermal analyses (DTA). Glass-ceramics comprising Bi2WO6 nanocrystallites with high optical transparency were obtained by controlled heat-treatment of the glasses at 723 K for 6 h. High resolution transmission electron microscopy (HRTEM) of the glass-ceramics demonstrate the presence of nearly spherical nanocrystallites (2-33 nm range) of Bi2WO6 embedded in Li2B4O7 glass matrix. The dielectric constants of both the as-quenched glasses and glass-ceramics decrease with increase in frequency (40 Hz to 100 kHz) at 300 K. Interestingly, the dielectric constant of the as-quenched glass undergoes a maximum around the crystallization temperature of the host glass reaching an anamalously high value (approximate to 10(7)) at 800 K. Different dielectric mixture formulae were employed to analyze the dielectric properties of these glasses and glass-ceramics. The optical properties viz. transmission, optical band gap energy and second harmonic generation (SHG) of these transparent glass-ceramics have been found to be compositional and crystallite size dependent. (C) 2001 Elsevier Science B.V. All rights reserved.
|Item Type:||Journal Article|
|Additional Information:||Copyright of this article belongs to Elsevier Science.|
|Department/Centre:||Division of Chemical Sciences > Materials Research Centre|
|Date Deposited:||18 Mar 2009 11:09|
|Last Modified:||19 Sep 2010 04:54|
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