Prepeak and First Sharp Diffraction Peak in the Structure Factor of (Cs2O)0.14(B2O3)0.86 Glass: Influence of Temperature

Abstract

Neutron diffraction measurements on (Cs₂O)_0.14(B₂O₃)_0.86 glass were performed at varying temperature over an extended range from room temperature to 800 K. It was found that, in the same Q range where the first sharp diffraction peak (FSDP) is observed in the static structure factor of almost all glass-forming systems, cesium borate glass shows two peaks. The intensities of these peaks increase with temperature, and their positions shift to lower Q values, in agreement with the peculiarities of the FSDP of network glasses. A description of this anomalous temperature dependence in terms of thermal relaxations of strained bonding arrangements of boron oxide units lying on the boundaries of cages present in the boron skeleton matrix is suggested. By comparing the diffraction patterns of a (Cs₂O)_0.14(B₂O₃)_0.86 sample before and after a high-temperature thermal treatment with the spectra of cesium crystals, a correspondence between the medium-range structure in the glass and the related crystalline phases has been inferred.