Ceramics-Silikáty 67, (2) 217 - 226 (2023)

Metaphosphate glasses Zn_aCu_(1-a)(PO₃)₂ and Ca_bCu_(1-b)(PO₃)₂ were prepared with the aim of studying the effect of different cations on solubility in water, on volume homogeneity and on the thickness of the surface layer. The relative ionicity of the Me-O(-P) bond (Me = Zn, Ca, and Cu) was determined using relative polarizability obtained by analyzing the Raman spectra. It was determined that the relative ionicity, i.e. the polarity of the bond, increases from the Cu donor-acceptor bond through the relatively covalently bound Ca to the significantly polar Zn bond. Compared to copper, both zinc and calcium reduce the compactness of the glass structure, of course to a different extent, and thus affect the coefficient of thermal expansion as well as the glass transition temperature. As can be expected, both from the relative ionicity and the effect on the compactness of the structure, the greatly increased solubility of glasses in water when replacing copper with calcium or zinc confirmed the reality of the conclusions about their influence on the properties of glasses. By dissolving glasses in water, the thicknesses of the surface layers were determined, which increases significantly from copper to calcium to zinc. Furthermore, phase segregation in the glass volume was identified.