Anelasticity of Glass: II, Internal Friction and Sodium Ion Diffusion in Tank Plate Glass, A Typical Soda‐Lime‐Silica Glass

The internal‐friction peak observed near room temperature in tank plate glass at a period of the order of seconds and previously attributed to sodium ion diffusion is further discussed. The temperature of maximum internal friction is shown to vary with the frequency of vibration with an activation energy of about 16 kg.‐cal. Per mole for air‐chilled glass fibers. Likewise, the activation energy for the electrical resistivity of the chilled glass is about 16 kg.‐cal. Although the activation energy for sodium ion diffusion and alkali durability is about 21 kg.‐cal., it too can be properly interpreted to confirm that the internal friction peak is caused by sodium ion diffusion. The internal friction peak is much broader than can be accounted for by a single relaxation mechanism. However, a dispersion of relaxation mechanisms is consistent with the accepted theory of randomness in the silica network.