Short-Range Order Details of Metaphosphate Glasses Studied by Pulsed Neutron Scattering

Details of the short-range order of the binary metaphosphate glasses AIP and PbP and the ternary glass system ZnO-MgO-2P have been studied by pulsed neutron scattering which provides a measuring range up to about Q = 500 nm . The splitting of the P-O peak in the distance correlation functions attributable to the different bond lengths for the non-bridging and bridging oxygens was found to decrease with increasing field strength of the network-modifier cations. For the ternary system ZnO-MgO-2P the peak in the distance correlation function, T(r), produced by the first oxygen neighbours around Zn and Mg was separated by the additional use of the X-ray structure factor. The distances r and r extracted from the separated peaks are slightly different from those obtained from the binary glasses ZnP and MgP . The metal-oxygen coordination numbers were found to be N =4.5 and N = 5.5. For the two binary systems the coordination numbers Al-0 and Pb-0 were obtained to be 7 and 5, respectively.