Effects of samarium (III) oxide content on structural investigations of the samarium–vanadate–tellurate glasses and glass ceramics

Glasses of the system xSm2O3∙(100-x)[6TeO2∙ 4V2O5] where 0 ≤ x ≤ 50 mol% were prepared and investigated. IR and UV–VIS spectra show that with increase x, the network continuity breaks down with the formation of the larger numbers of non-bridging oxygen. The accommodation of the network with the excess of oxygen ions is possible by the depolymerization of the vanadate network in shorter chains, especially ortho- and pyrovanadate structural units. In order to improve the local orders and to develop crystalline phases the glass samples were kept at 275° C for 7 h. Some structural changes were observed and new crystalline phases, namely Te2V2O9 and SmVO4 crystalline phases appeared in the structure of the samples. Our UV–VIS spectroscopic data show the conversion of the Sm+ 3 to Sm+ 2 species in same time with the oxidation of V+ 3, + 4 to V+ 5 ions.