Raman spectroscopy of RDX crystals shocked along different orientations

Raman spectroscopy of the CH stretching modes was used to investigate the molecular level response of hexahydro-1,3,5-trinitro-s-triazine (RDX) to shock compression. Single crystals of [111], [210], and [100] orientation were compressed under stepwise shock loading to peak stresses from 3.0 to 5.5 GPa. Similar frequency shifts were observed for all three orientations below 3.5 GPa. Significant spectral changes were observed in crystals shocked above 4.5 GPa. These changes were consistent with the alpha - gamma phase transition observed under static compression. No apparent dependence on crystal orientation was observed to 5.5 GPa. The phase transition had an incubation time of about 100 ns when RDX was shocked to 5.5 GPa peak stress.