Abstract
The viscosity measurements in the system Na2O-SiO2-MgO have been conducted to find out the behavior of the MgO in this system.
When MgO was added to the melt having the composition of Na2O/SiO2=1⁄4, the viscosity was almost constant up to about 10 mol%MgO content, but thereafter it decreased wih increasing MgO content. In the case of the melt having the composition of Na2O/SiO2=3⁄2, the viscosity increased with increasing MgO content. This may be considered that the MgO will act as a network former like SiO2 in this system.
The viscosity coefficient gave a linear relationship with a parameter of SiO2+0.33MgO, where 0.33 is the ratio of ion-oxygen attraction MgO in the tetrahedral site and SiO2.
The infrared and far-infrared absorption spectra were observed to investigate the structure of quenched glass. The absorption bands of Mg-O for both (MgO4) and (MgO6) were observed in the region of far-infrared absorption spectra.
