Eur. Phys. J. B 83, 133-141 (2011)
https://doi.org/10.1140/epjb/e2011-20211-2

Structure-properties changes in ZnO-PbO-GeO₂ glasses

¹ Department of Essential Science, Industrial Education College, Beni-Suef University, Egypt
² Glass Research Group, Physics Department, Faculty of Science, Mansoura University, Mansoura, 35516, Egypt

Corresponding author: ^a emansour68@gmail.com

Received: 18 March 2011
Published online: 23 September 2011

Abstract

We have studied the structure of ZnO-PbO-GeO₂ glasses by Fourier transform infrared spectroscopy and showed that the analysis of the vibrational spectra can lead to a quantitative description of the network structure in terms of the fraction of the local germanate polyhedra. The presence of GeO₄, GeO₆ and GeO₄ with NBOs units was evidenced in the studied glass network. The initial additions of ZnO would introduce modifier Zn²⁺ ions at the expense of the former PbO₄ units. With increasing ZnO content, ZnO₄ tetrahedra would mainly replace modifier PbO. The decrease in density when introducing ZnO at the expense of PbO content is not only due to the vast difference in molecular mass between PbO and ZnO, but also due to the formation of Q² and Q³ units. The glass network of the investigated glasses posseses a more covalent character upon replacing ZnO for PbO. This is the reason for increasing the microhardness and the glass transformation temperature of the glasses investigated with increasing zinc oxide content. The change in the conductivity at certain temperature not only attributed to the change in the covalency of the glass matrix upon replacing PbO by ZnO but also due to a change in the strain energy because of the change in V_m.