Photodissociation of glycidyl azide polymer with a Nd:YAG laser at 1.064 μm

Glycidyl azide polymer was dissociated with infrared radiation at 1.064 μm from a Nd:YAG laser; gaseous products were detected in situ with a Fourier-transform infrared spectrometer. On irradiation of this polymer under vacuum, CO, C2H2, and HCN are the major products, and C2H4, CH4, NH3, and CO2 are minor products. As H2CO is absent; this distribution of products resembles a distribution obtained from irradiation with a pulsed CO2 laser more than that with a continuous wave CO2 laser or with flash pyrolysis, which methods produce abundant H2CO, NH3, and other hydrocarbons. Yields of C2H2 in the present experiments much greater than those with experiments using a pulsed CO2 laser indicate that irradiation of glycidyl azide polymer with a Nd:YAG laser achieves an instantaneous temperature much greater than with other methods and consequently causes the most extensive rupture of skeletal bonds. When the gases Ar and N2 were added, the effects were similar, except for evidence of reaction of CH with N2 to form HCN at the expense of C2H2. Gaseous O2 reacts with primary reactive species to form predominantly CO and CO2, and a small amount of NO2. Ignition occurs under conditions with the pressure of O2 exceeding 0.40 bar and a laser fluence of not, vert, similar7 J/cm2. The effects of laser energy and of external gas pressure on product branching and on the mechanisms of decomposition are discussed.