Stress Relaxation Modulus of a Commercial Glass

Abstract

The stress relaxation modulus in compression of a container glass was investigated over a wide range of strain, time, modulus, and temperature. The glass is a linear viscoelastic liquid up to 2% strain, and the modulus is a smooth function of time, with no pseudorubbery plateau apparent down to a modulus of 10° dynes/cm2. The data cover 4 decades in time and a range of almost 100°C above the glass transition, T0=536°C. Within experimental error, changes in temperature simply shift the modulus‐vs‐time curve along the time axis without altering its shape. This behavior implies that the same mechanism controls both the bulk and shear spectra. The shift factors fit the WLF equation well with values for the parameters c1 and c2 of 16.7±0.2 and 345±5°C, respectively. Data from the literature for silicate glasses agree with these parameters.

Finite element modelling of stress relaxation in glass lens moulding using measured, temperature-dependent elastic modulus and viscosity data of glass

“…This indicates a thermo-rheologically simple (TRS) behaviour exhibited by both glasses in the given temperature range. Most oxide glasses are known to exhibit similar behaviour [2][3][4]13].…”

“…This time-dependent deformation results in the decay of the applied load and is termed as relaxation. Stress relaxation in glass at high temperature has extensively been studied [2][3][4]. Viscoelastic stress relaxation can best be illustrated with the help of mechanical models-combinations of springs and dashpots, where the spring represents the elastic behaviour and the dashpot the viscous behaviour.…”

A study on ion‐exchanged, soda‐lime glass’s residual stress relationship with K+/Na+ concentration

“…In order to investigate the stress relaxation time constants, , dependence on the K 2 O concentration (and nominally eliminating the effects of temperature), the master relaxation curves had to be obtained at = 450°C. This task was accomplished by following the methodology outlined by Mills and Sievert and Eisenberg and Takahashi . Although for the shift factor, , was accurately described by the WLF Equation, for , a modified equation has been shown to be more appropriate:…”

“…The dependence of soda‐lime glass's (SLG) stress relaxation on the molten salt bath's temperature has been extensively studied for fixed chemical compositions and temperatures below the glass transition (ie, T = 385°C–550°C) . In the past, equivalent temperature‐induced time shifts were utilized to adjust the stress relaxation's “master curve” function and account for temperature variations near the T g . Mills and Sievert proposed using a “shift factor” (log a T ) to shift the relaxation function along the logarithmic timescale.…”

“…In the past, equivalent temperature‐induced time shifts were utilized to adjust the stress relaxation's “master curve” function and account for temperature variations near the T g . Mills and Sievert proposed using a “shift factor” (log a T ) to shift the relaxation function along the logarithmic timescale. If the heat‐treated material had a single relaxation time obeying an Arrhenius‐type relation, the shift factor could be expressed as follows:…”