Effect of water on sodium ion mobility in sodium magnesium aluminosilicate glasses by internal friction analysis

Abstract The effect of water on the internal friction of SiO 2 –Al 2 O 3 –Na 2 O–MgO glasses with water content up to 0.070 mol/l was determined. For (74 − x)SiO 2 –xAl 2 O 3 –(26 − y)Na 2 O–yMgO glasses in which 0 ≦ x ≦ 3 and 0 ≦ y ≦ 16, the low temperature friction peak below 200 °C caused by the stress-induced movement of sodium ion shifts to higher temperature, and its activation energy becomes larger with increasing water content. This result suggests that the low temperature motion of Na + ion (γ relaxation) becomes slower by addition of water. For 69SiO 2 –5Al 2 O 3 –13Na 2 O–13MgO glass, however, adding water enhanced sodium ion movement since aluminate tetrahedral became charge balanced by H + instead of Na + cation, thereby inducing γ relaxation.