On the structure of glass of the PbO-B2O3-SiO2 and CdO-SiO2-B2O3 systems

Using the method of X-ray scattering at large angles, the structure of single-phase glass of the PbO-B2O3-SiO2 and CdO-B2O3-SiO2 systems has been studied. The glass of the two-component PbO-B2O3 and PbO-SiO2 systems of the three-component PbO-B2O3-SiO2 system, containing from 10 to 60 mol % of SiO2 at equal fractions of B2O3 and PbO, and the glass of a number of compositions of the CdO-B2O3-SiO2 system containing from 30 to 60% of CdO are investigated. A change in the prevailing interatomic spacings in the dependence on the glass composition is determined. The boron-oxygen network provides the orderliness in the distribution of ions-modifiers observed at distances on the order of 6 Å. It is found that in contrast to boron-oxygen network, the silicon-oxygen network does not have the ability to order the distribution of the ions-modifiers.