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, Sm2O...