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

•Internal friction for SiO2–Al2O3–Na2O–MgO glasses containing water was measured.•Low temperature friction peak due to alkali ion motion changes with increasing water.•Low temperature relaxation changes by the presence of proton and aluminum ions.

The effect of water on the internal friction of SiO2–Al2O3–Na2O–MgO glasses with water content up to 0.070 mol/l was determined. For (74 − x)SiO2–xAl2O3–(26 − y)Na2O–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 69SiO2–5Al2O3–13Na2O–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.