Phenomenon of Eu3+ self-reduction induced by B2O3 configuration structure in sodiumborate glasses

Abstract

The self-reduction of Eu3+ to Eu2+ is realized in Eu2O3 doped sodiumborate glasses in the air condition. With increasing in B2O3 concentration, the blue emission of Eu2+ is significantly enhanced while the 615 nm emission of Eu3+ is soon decreased. The calculation result indicates that the [BO4] tetrahedron are gradually replaced by [BO3] triangle with increasing in the network former B2O3 in the glass matrix. According to the infrared and Raman spectra analysis, the high polymeric network structure is depolymerized mainly from the complicated framework by [BO4] linking with [BO3] to the smaller planar BO3-triangles consisted structure units. Accordingly, the characteristic vibrations of the relevant peaks are reflected by the orthoborate groups, boroxol rings, and pyroborate structure units, etc., decomposed in the sodiumborate glasses. In addition, the effect of the structure variation on the mechanism of Eu3+ reduction in borate glasses is discussed.