Laser-induced decomposition mechanism of novel polynitrogen energetic material 4,4′-azobis (1,2,4-triazole) (ATRZ): Time-resolved evolution of gaseous products

The novel polynitrogen energetic material 4,4′-azobis(1,2,4-triazole) (ATRZ) has attracted significant research interest due to its high nitrogen content and excellent detonation performance. However, its rapid decomposition mechanism under laser irradiation, particularly the time-resolved evolution of gaseous products, remains unclear. This study presents a comprehensive investigation into the decomposition kinetics and gaseous products evolution of ATRZ under laser irradiation in both air and argon atmospheres, utilizing synchronized time-resolved schlieren imaging and laser induced plasma spectroscopy (LIPS). In an air atmosphere, the primary decomposition products are N₂, CO, CO₂, NO, and NO₂. Among them, CO₂ has the highest concentration, which confirms the oxidative participation of atmospheric oxygen. A distinct temporal evolution is observed, wherein nitrogen-containing species (N₂, NO, and NO₂) are generated prior to carbon-containing and hydrogen-containing products. Transient spectroscopic signatures of C₂ and CN radicals are detected during the initial reaction stage, indicative of incomplete molecular dissociation and subsequent fragment recombination, followed by their oxidation into CO, CO₂, NO, and NO₂ compounds. In contrast, under an inert argon environment, the absence of oxidative pathways results in sustained C₂ and CN emissions alongside negligible CO₂ formation. Schlieren imaging reveals a self-sustained combustion process occurring on millisecond timescales exclusively in air, which is attributed to sustained oxidation of carbon-enriched clusters, a phenomenon entirely absent under argon. The findings highlight the crucial impact of ambient oxygen on the decomposition mechanism and energy release dynamics of ATRZ, offering fundamental insights into the environmental dependence of energetic material degradation pathways.