Using 70‐ns bursts of 3‐MeV average energy electrons as the heating source, inertial thermomechanical stresses were produced inX‐cut quartz disks. The range of peak absorbed energy density was from 30 to 360 cal/g. The stress pulses propagated through the samples (direction perpendicular to thecaxis), and the ensuing rear surface motion was recorded with a laser interferometer. At the highest dose, the peak temperature produced in the absorber was calculated to exceed 1600 K, well in excess of the &agr;‐&bgr; transition temperature. Comparison of the experimental results with a model calculation, taking into account the shift of transition temperature with pressure, suggests that the phase transition occurred and that the response was not associated with a metastable state.