Structure of MoO3-WO3-La2O3-B2O3 glasses and crystallization of LaMo1 − xWxBO6 solid solutions

The glasses with the nominal compositions of (50 − x)MoO3-xWO3-25La2O3-25B2O3 with x = 0, 10, 20, 30, 40, and 50 (mol%) were prepared using a conventional melt quenching method and their structure and crystallization behavior were investigated from Raman scattering spectroscopy, infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction analysis (XRD). It was found that the glass transition and crystallization temperatures and the thermal stability against crystallization increase with the substitution of WO3 for MoO3. The formation of LaMox − 1WxO6 solid solutions was found in the crystallized samples. It was proposed that the glass structure is built up mainly from tetrahedral (MoO4)2 − and (WO4)2 − units providing the Raman bands of around 330, 830, and 920 cm− 1 and the network consisting of B-O-B bonds. The partial transformation from (WO4)2 − to octahedral WO6 units was proposed to occur when the content of WO3 increases.