Investigation of thermal stability and fingerprint spectra of energetic 1,2,3-triazole using pulsed photoacoustic pyrolysis technique

Abstract

This paper reports on a comparative study of UV and visible radiation-based pulsed photoacoustic (PA) pyrolysis technique examining thermal stability and acoustic fingerprint spectra of a newly synthesized high-energy molecule named 1-(2,4-dinitrobenzyl)-4-nitro-1H-1,2,3-triazole (S6). The thermal PA spectra of S6 were recorded in temperatures ranging between 30 and 350 °C using second and fourth harmonic wavelengths (i.e., 532 and 266 nm), obtained from Q-switched Nd:YAG laser pulses of duration 7 ns at 10 Hz repetition rate. The PA results are further compared with TG–DTA data to understand the release mechanism of NO2 along with other gaseous by-products. The difference in thermal PA spectra of S6 which follows two different mechanisms, such as vibronic transition V–V and V–T relaxation in NO2 functional group, while electronic π* ← n transition in the entire molecule, is due to selection of visible and UV wavelengths. In addition, the effect of data acquisition time and incident laser energy has been examined in order to understand the behavior of acoustic modes of a PA cavity at the desired vapor temperature. The stability of the compound is also evaluated on the basis of thermal quality factor (Q), of PA cavity.