Vibrational spectroscopy of highly iron doped B2O3–Bi2O3 glass systems

Glass systems of composition 95%[xB2O3(1−x)Bi2O3]5%Fe2O3 with different Bi/B nominal ratios (0.07⩽x⩽0.90) have been investigated by means of Raman and infrared spectroscopy in order to obtain information about the competitive role of B2O3 and Bi2O3 in the formation of the glass network. The glass samples have been prepared by melting at 1100 °C and rapidly cooling at room temperature. The samples have been further kept at 575 °C for 10 h in order to relax the glasses structure as well as to improve the local order and to develop the new formed crystalline phases. The influence of both Bi2O3 and Fe2O3 on the vitreous B2O3 network as well as the local order changes around bismuth and boron atoms in as prepared and heat-treated samples have been studied. Structural modifications occurring in the heat-treated samples compared to the untreated glasses have been pointed out.