Lithium phosphate glasses with different iron oxide contents were prepared using a rapid quenching technique and their glass transition temperatures (Tg), densities (d) and refractive indexes (n) were measured.X-ray photoelectron spectroscopy(XPS), infrared spectroscopy(IR) and Mossbauer spectroscopy have been used to study structure of the glasses and oxidation states of iron. These results indicate that both the Fe2+ and Fe3+ ions are present in the phosphate glasses, and that Fe2+ ions are coordinated with both four and six oxygen, but Fe2+ ions are only in six coordination, and that the physical and optical properties depended on the Fe2+/Fe ratio and Fe3+(4-coordinated)/Fe ratio. The XPS spectra and Mossbauer effect measurements showed that an increase in the Fe203 content causes a decrease of Fe2+/Fe ratio and an increase Fe3+(4-coordinated)/Fe ratio. The infrared measurements showed that an increase in the Fe203 content causes a change in coordination from Fe06 to FeO4.
|