Application of light reflectance change for investigation of thermal stability of energetic materials*

Commonly accepted method for testing thermal stability of energetic materials is thermal analysis. The most popular method of thermal analysis are differential scanning calorimetry (DSC) and differential thermal analysis (DTA). Thermomicroscopy is an another valuable method for detection of physical and chemical changes during heating of the sample. A combination of the methods described above is the analysis of the change in the light reflectance from the sample as a function of its temperature. This method was applied for investigation of thermal stability of common explosives like 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX), pentaerythritol tetranitrate (PETN) and relatively new explosive with low sensitivity 3-nitro-1,2,4-triazol-5-one (NTO). On the curves of reflectance changes as a function of temperature registered for RDX and NTO, new undescribed previously processes were observed. An attempt was made to explain these new phenomena by comparing the new data with well-known DSC curves for investigated compounds. Diphase model of the solid substance decomposition was proposed to describe the observed phenomena.