Elastic Aftereffects and Dielectric Absorption in Glass

Abstract

Taylor and Doran have found that in stabilized glasses the total elastic adjustment under a given load may be represented as the sum of several terms of the type l=l0e−kt, and have drawn the conclusion that there are several sizes of complex silicate ions in glass which respond independently and with different rates to applied stress. Hopkinson proposed that there are several independent ``elements'' responding to the application of an electric field to a glass condenser, and von Schweidler showed that the anomalous charging current accompanying dielectric polarization is the sum of several terms of the type i=Ae−t/T. This expression is identical in form with that for elastic polarization if the rate constant k is replaced by a characteristic relaxation time constant 1/T. The dielectric phenomena thus appear to support the concept of independently acting ions in glass. This idea is in harmony with the x-ray evidence of a random ionic network, and with other physico-chemical evidence. An interpretation of memory phenomena such as reversal effects in glass and rubber has been offered. Such reversals appear to be due to the superposition of two or more independent operations with different rate constants and directions.