Influence of rare-earth oxides on structure and crystallization properties of Bi2O3-B2O3 glass

Bi2O3*B2O3 glasses doped with rare-earth oxides (RE2O3) (RE3+ = La3+, Pr3+, Sm3+, Gd3+, Er3+ and Yb3+) were prepared by the melting-quenching method. The relationships between composition and properties were demonstrated by IR, DSC, XRD and SEM analysis. The results show that the network structure resembles that of undoped Bi2O3*B2O3 glass, composing of [BO3], [BO4] and [BiO6] units. RE2O3 stabilizes the glass structure as a modifier. Transition temperature (Tg) increases linearly with cationic field strength (CFS) of RE3+. La2O3, Pr2O3, Sm2O3 and Gd2O3 are benefit to promote the formation of BiBO3 crystal. When Er2O3 and Yb2O3 are introduced, respectively, the main crystal phase changes to Bi6B10O24. Transparent surface crystallized samples are obtained by reheating at 460-540 deg C for 5 h. In this case, needle like BiBO3 crystal or rare-earth-doped BiBO3 crystal (PrxBi1-xBO3 and GdxBi1-xBO3) are observed, which is promising for non-linear optical application.