THERMAL-PROPERTIES OF MOLTEN BISMUTH GERMANATES

The temperature dependences of the density, the surface tension and th e viscosity of molten Bi4Ge3O12 and Bi12GeO20 were measured by the Arc himedian method, the ring method and the oscillation damping method, r elatively. The obtained values were compared with the previously repor ted values. The activation energies for viscous flow and the volumes o f the viscous flow unit were calculated from the temperature dependenc es of the viscosity. The liquid structure of Bi4Ge3O12 and Bi12GeO20 w as discussed based on these calculated values.