Influences of La3+ and Er3+ on structure and properties of Bi2O3-B2O3 glass

Bi2O3·2B2O3 glasses doped with La2O3 and Er2O3 were prepared by the melting-quenching method with AR-grade oxides. IR analysis was used to investigate the glass network structure. The characteristic temperatures including the glass transition temperature (Tg), crystallization temperature (Tp), and melting temperature (Tm) were estimated by DSC. The coefficient of thermal expansion (α), mass density (D), and Vickers hardness (Hv) were also measured. The results show that the basic network structure of Bi2O3·2B2O3 glasses doped with rare-earth oxides consists of chains composed of [BO3], [BO4], and [BiO6] units. La2O3 and Er2O3 act as network modifiers. As the doping concentrations of the rare-earth oxides were increased, Tg increased and α decreased, indicating that a more rigid glass was obtained. Er2O3 reduces the melting temperature and prevents glass crystallization. La2O3 contributes to the improvement of the microhardness of Bi2O3·2B2O3 glass.