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

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 hightemperature thermal treatment with the spectra of cesium crystals, a correspondence between the mediumrange structure in the glass and the related crystalline phases has been inferred.