Cadmium sulfide crystals were shocked along the c-axis to peak instantaneous stresses ranging from 27 to 53 kbar, above and below the phase transition stress of 32 kbar. Particle velocity measurements, using a VISAR system with nanosecond temporal resolution, were used to determine the time dependent mechanical response at the impact surface at higher time resolutions than those reported by Tang and Gupta, and to complement the recent electronic spectroscopy measurements. For experiments with longitudinal stresses above 32 kbar, but below 53 kbar, the instantaneous impact stress of the initial wurtzite phase is maintained for significant times before relaxing to a metastable state, and then further relaxing to the final rock salt phase. Transition rates and metastable state lifetimes are observed to be stress dependent. At 53.5 kbar impact stress, transition to a metastable state appears to be complete within 3 ns of impact, and the full relaxation to the rock salt phase indicates that the phase transition may proceed through multiple metastable states. Epoxy bonds with VISAR windows degrade the ability to accurately measure fast, stress-relaxing phenomena. ©2000 American Institute of Physics.