Some physical properties concerning the thermal conductivity data of BaO-containing silicate glasses in relation to structure

The thermal conductivity, density, refractive index and viscosity of glasses with base composition (wt%): Na₂O, 20; CaO, 15; SiO₂ 65, in which CaO is partially replaced by BaO, have been investigated.Both the thermal conductivity and the viscosity—temperature values progressively decreased by introducing BaO to replace CaO in the glasses. Meanwhile, this replacement caused an increase in other properties, i.e., density and refractive index. The experimental measurements and calculated values of either thermal conductivity or viscosity agree fairly well. The observed effects were correlated to factors such as polarization, field strength and ionic radii of the incorporated divalent cations, and their effect on the geometrical arrangement of the building units of the glassy network.