关键词: 四硼酸锂玻璃;光学带隙;折射率;桥氧

Abstract: (100-x) Li2B4O7-x(Bi2O3 · WO3 ) (5≤x≤20) glass was prepared by melt-quenching method.The density, absorption spectra and refractive index of the glasses studied were determined respectively by gravimeter , spectrophotometer and V prism refractometer .It is found that density and molar volume of glasses increase with the increase of Bi 2 O3 · WO3 contents.Conversely, oxygen packing density of glasses is found to decrease .The cut off wavelength shifts to the higher wavelength with the increase in x.The allowed indirect band gap energy , Urbach energy and Fermi energy , decrease with the increase in x, but the refractive index is increased .The addition of Bi 2 O3 · WO3 content may convert some of the bridging oxygens to the non-bridging oxygens in the glass network .The changes of glass optical properties relate to this conversion .

Key words: Li2 B4 O7 glass;optical band gap;refractive index;bridging oxygen