Properties and structure of germanium-containing lithium aluminoborate glasses

• Published in: Journal of materials science. Materials in electronics 2002-09, Vol.13 (9), p.537-542
• Main Authors: Abo-Naf, S M, Darwish, H, El-Desoky, M M
• Format: Article
• Language: English
• Subjects: Conductivity; Density; Electronics; Fourier transforms; Germanium oxides; Glass; Lithium; Resistivity; Temperature; Thermal expansion
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1023/A:1019617529164

Glasses of the system Li^sub 2^O-Al^sub 2^O^sub 3^-GeO^sub 2^-B^sub 2^O^sub 3^ have been investigated. The effect of replacement of the B^sub 2^O^sub 3^ by GeO^sub 2^ on the physicochemical properties of the glasses has been studied. The density and the refractive index were found to increase as the GeO^sub 2^:B^sub 2^O^sub 3^ ratio (r) increases. In contrast, the molar volume was found to decrease as r increases. Dilatometric measurements showed that the thermal expansion coefficient (α) increases with the increase of r whereas both of the glass transition temperature (T^sub g^) and the softening point (T^sub s^) decreases with increasing r. Fourier transform infrared (FTIR) spectroscopy revealed that BO^sub 3^ structural units increase at the expense of BO^sub 4^ units as r increases. It is indicated also that GeO^sub 6^ units are the preferred germanium structural units that participate into the glass network. The electrical conductivity was found to decrease with increasing r. This was attributed to the large difference between the two atoms (Ge and B), which increases the stability and therefore decreases the conductivity of the investigated glasses. The conductivity results were correlated with those from the FTIR study.[PUBLICATION ABSTRACT]