Thermal wave imaging combined with stress pattern analysis by measurement of thermal emission (SPATE) is used to study the failure behavior of a polypropylene (PP) + ethylene propylene diene (EPDM) polymer blend. Images corresponding to a propagating crack in a single edge-notched specimen were measured at three rates of testing : 4 mm/min, 8 mm/min, and 20 mm/min. Conversion to stress values is made through use of a thermoelastic function. It is found that in a 4 mm/min test the crack tip radii blunt rather than propagate with little initiation. Large-scale necking precedes fracture. At 8 mm/min, some blunting occurs, followed by fast crack propagation. At 20 mm/min, fast crack propagation occurs. The images are digitized to obtain the values of the temperatures at every point in the sample. Data corresponding to the plane of the propagating crack over the span of the test are presented.