Bulk model of laser ablation of polymers

The model of laser ablation driven by a bulk photothermal reaction is considered. Stationary wave solutions are obtained and analyzed. In the case of a simple photothermal bond-breaking reaction, it is possible to reduce this bulk ablation model to the surface evaporation model with some apparent activation energy. A more complicated model of laser ablation, taking into consideration a photothermal modification of broken bonds within the bulk of material, is also studied. The existence of the second threshold related to multiple-shot and long pulse irradiation experiments has been demonstrated. It is shown that the effect of modification on the ablation kinetics qualitatively depends on the interrelation between activation energies of two considered bulk reactions. q1998 Elsevier Science B.V.