Kinetics and dynamics of heat-flow-induced birefringence in a glass: Modulation polarimetric representation

The birefringence induced by thermal stress in a quartz glass plate sample with a small temperature gradient has been measured using the modulation polarimetry technique. The stress distribution along and across the direction of the heat flow at specific points in time has been obtained, as well as its dependence on the time in specific coordinates of the heat flow. The inverse problem of transient thermoelasticity has been solved by graphical integration of experimental characteristics. The results obtained have the form of temperature dependences varying in time and space. It has been found that the dynamics of the point of maximum curvature of the temperature function T(t) is a characteristic of the thermal front during the establishment of a steady-state heat flow. It has been shown that the characteristics of relaxation of thermal stress and temperature contain information on the properties of a “heater-sample-surrounding air” system.