Effect of tin and gold on sodium ion movement in a sodium silicate glass

Since Roman times the addition of tin is known to induce a deep red color in ruby glass based on gold nanoparticles, but very little information is available on how electrical properties of such glasses are affected by the presence of gold nanoparticles or tin doping. Therefore, we have explored the electrical effects of the addition of tin (a parts per thousand currency sign0.1 mol%) to sodium trisilicate glass, which was doped with 0.1 mol% gold. The addition of both 0.1 mol% gold and 0.1 mol% tin increases the DC electrical conductivity, which arises from sodium ion transport, compared to base glass. The activation energy of DC conductivity decreases when the amount of tin increases with the gold content held constant. The mechanism of the enhancement of Na+ ion transport appears to be different for the two types of dopings: Au doping causes general expansion of molar volume whereas tin doping enhances the polarizability of the medium.