Influence of rare-earth oxides on structure and crystallization properties of Bi_2O_3-B_2O_3 glass

摘要

Bi_2O_3·B_2O_3 glasses doped with rare-earth oxides (RE_2O_3) (RE~(3+) = La~(3+), Pr~(3+), Sm~(3+), Gd~(3+), Er~(3+) and Yb~(3+)) 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 Bi_2O_3·B_2O_3 glass, composing of [BO_3], [BO_4] and [BiO_6] units. RE_2O_3 stabilizes the glass structure as a modifier. Transition temperature (T_g) increases linearly with cationic field strength (CFS) of RE~(3+). La_2O_3, Pr_2O_3, Sm_2O_3 and Gd_2O_3 are benefit to promote the formation of BiBO_3 crystal. When Er_2O_3 and Yb_2O_3 are introduced, respectively, the main crystal phase changes to Bi_6B_(10)O_(24). Transparent surface crystallized samples are obtained by reheating at 460-540℃ for 5h. In this case, needle like BiBO_3 crystal or rare-earth-doped BiBO_3 crystal (Pr_xBi_(1-x)BO_3 and Gd_xBi_(1-x)BO_3) are observed, which is promising for non-linear optical application.