The performance and sensitivity of aged composite explosives based on the epsilon polymorph of hexanitrohexaazaisowurtzitane (E-CL-20) have been evaluated with the laser-induced air shock from energetic materials (LASEM) technique using only milligram quantities of material. The LASEM results demonstrated reduced explosive performance (i.e., lower estimated detonation velocities) and higher sensitivity to ignition with increasing ageing. Chemical analysis of the explosive formulation subjected to ambient and accelerated aging was conducted to help understand the LASEM results. The Fourier Transform Infrared (FTIR) spectra revealed no evidence for conversion to lower-energy polymorphs. Based on the desorption gas chromatography/mass spectrometry (D-GC/MS) results, the observed decrease in performance and increase in sensitivity for the explosive powder aged at 100 degrees C (relative to ambient and 70 degrees C aging) have been attributed to changes related to solvent inclusions in the molding powders.