FTIR and Raman spectroscopic investigation of some strontium-borate glasses doped with iron ions

摘要

Structural investigation of xFe_2O_3·(100 - x) [3B_2O_3-SrO] glass system, with 0 ≤ x ≤ 40 mol%, was performed by means of X-Ray diffraction (XRD), Fourier transform infrared (FTIR) and Raman spectroscopies. The purpose of this work was to investigate the structural changes that appear in the 3B_2O_3·SrO glass matrix with the addition and increasing of iron ions content. The XRD pattern for the prepared samples shows that vitreous phase is present only for x ≤ 40 mol%. For sample containing 50 mol% Fe_2O_3 was evidenced the presence of a unique crystalline phase, Fe_2O_3, embedded in an amorphous matrix. FTIR data show that BO_3 and BO_4 are the main structural units of the glass system and the iron ions are located in the network. The Raman spectrum of glass matrix indicates a structure with several borate groups (di-, meta-, pyro-borate, etc.). In higher concentrations the iron ions break the regulate glass network and determines the appearance of BO_4 isolated units.