UV-laser Ablation of Polymerized Resin Layers and Possible Oxidation Processes in Oil-Based Painting Media

Abstract

The use of short-pulse lasers for ablating polymerized resin layers has been examined in detail. In particular examples of KrF excimer laser ablation of varnishes, artificially or physically aged, are presented. Ablation rate data, operational processes and critical experimental parameters are discussed. The aim is to develop a methodology for finding the optimal laser parameters, under which, no harm is done to the pigments below the usually unknown varnish layers. For this, Gas Chromatography coupled to mass analysis (GC-MS) has been used to assess the photochemical oxidation of the binding medium when different laser parameters are used. The combined results from the above studies lead to an understanding of UV-laser ablation in polymerized resins in relation to possible photo-oxidation processes.