Irradiating a polymer surface with a pulse of UV light which is emitted by an excimer laser may induce emission of matter or ablation. This well documented phenomenon takes place at and above a given value of the pulse energy density (or fluence, in J/cm(2)), the ablation threshold eo. Above threshold, ablation appears at first to increase with fluence at a constant rate chi (in cm(3)/J) and tend to saturate upon further increasing fluence, thus setting a maximum ablation depth per pulse z(0). All three quantities (epsilon (0), chi and z(0)) are quite generally evidenced experimentally for all polymers and their values are characteristic of the behavior of each of these materials under such irradiation conditions. Consequently, they might be expected to carry specific information on the physics of the ablation process itself and could help identifying each polymer. The object of this presentation is precisely to address that issue. This is done through a comprehensive description of the dynamics of the ablation process, voluntarily discarding thermal aspects that have long been proposed to be responsible for such a non-equilibrium phenomenon. Meanwhile, a close relation may be established between the above three quantities and the intimate structure of the polymers. This is exemplified in this work for a family of three related high temperature polymers: polyethyleneterephtalate (PET), polyethersulfone (PES) and polyphenylenesulfide (PPS). (C) 2001 Elsevier Science B.V. All rights reserved.
