Mechanical stress relaxation in inorganic glasses studied by a step-strain technique

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Date

1991-06-11

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Elsevier Science

Abstract

A computer-controlled transient viscoelastometer, which is an adaption of the Rheovibron, has been developed to study the mechanical stress relaxation of amorphous materials over a range of more than five decades in time. The instrument was used to investigate the degree of non-exponentiality of the tensile stress autocorrelation function of AgI---Ag2SO4---Ag2WO4 and Ge---As---Se glasses. Upon variation of the composition, both ternary systems show large variations of the smearing of the calorimetric glass-transition anomaly. For most cases low-noise decay functions could be observed which are well fitted by stretched exponentials. For 50AgI·25Ag2SO4·25Ag2WO4 an exceptionally broad distribution of relaxation times is found. This is consistent with the sub-Tg specific heat peak previously observed in these mixed oxyanion glasses. For pure amorphous selenium two distinct relaxation processes are observed.

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Böhmer, R.; Senapati, H.; Angell, C. A.: Mechanical stress relaxation in inorganic glasses studied by a step-strain technique. In: Journal of Non-Crystalline Solids Jg. 131-133(1991), S. 182-186, doi: 10.1016/0022-3093(91)90295-H.