Infrared laser ablation of polymers

Ablation produced by 10.6 μm laser irradiation of eleven polymers is reported. Polymers which formed a carbonaceous residue were found to have much higher ablation energies than cleanly ablating polymers. All non‐char forming polymers studied had observed laser ablation energies in the range 3.4‐3.9 KJ/g except for poly (α‐methylstyrene) which had a value of 2.4 KJ/g. The low value forpoly (α‐methylstyrene) is attributed to an exceptionally efficient depolymerization. The observed ablation energy of poly (methyl methacrylate) was found to decrease with increasing irradiance up to about 15 watts/cm2, reaching a constant value of 3.5 KJ/g at irradiances between 20 and 2600 watts/cm2. The proposed process of laser ablation is one that involves random fragmentation resulting from the accumulation of vibronic energy.