Structural investigation of CuO containing strontium-borate glasses by means of EPR and IR spectrometry

Two vitreous oxide systems, i.e. 2B(2)O(3) . SrO and 2B(2)O(3) . SrF2 containing CuO within a wide range of concentration, were investigated. The influence of a gradual increase in CuO content on the glass structure and the effect of the oxygen partial replacement by fluorine atoms were revealed. EPR absorption spectra show Cu2+ ions in axially distorted octahedral environments. No clusters of Cu2+ ions were detected. Mixed valence states of copper ions were revealed, especially at high CuO content. The influence of composition changes when using SrO or SrF2 as network-modifiers upon the valence state and distribution of copper ions was also revealed. By means of IR spectroscopy the dependence of the BO4/BO3 ratio on the CuO content and the presence of F atoms in the glass matrix was estimated.