Synthesis and properties of neodymium containing oxide fluoride glasses

New oxide fluoride glasses containing a large amount of Nd3+ were synthesized in NdF3–AlF3–GeO2 and NdF3–BaF2–GeO2 systems. The melting temperature was at 1200–1400 °C. The glass transition temperatures were 800–850 °C. The glasses synthesized in this study had the refractive indices (n) of 1.56–1.74, except for 25NdF3·12.5BaF2·62.5GeO2 glass having n of >1.77. The fluorine in the starting mixture tended to go away during the melting due to the sublimation of AlF3 (or GeF4) and the pyrohydrolysis of fluorides. The fluorine content of 40NdF3·20BaF2·40GeO2 glass (19.3 wt.%) decreased to 5 wt.% during melting due to sublimation of GeF4 and pyrohydrolysis of the fluorides during melting. The maximal contents of Nd3+ in the glass were 63 and 58 cation% for NdF3-AlF3-GeO2 and NdF3-BaF2-GeO2 systems, respectively. The results suggest that fluorine was uniformly present in the glass network.