Radiation curing is, nowadays, a well-established technology which develops and grows rapidly on an industrial scale. Originally, the most emergent applications were related to the UV-curing of coatings. Reprography (printing plates, integrated circuits, photoresists, solder masks) represents a second class of applications. Lastly, laser induced curing - holographic recording, 3D pattern formation under laser exposure, holographic optical elements - appear as new, promising and fantastic techniques in the near future. The practical development of these technologies obviously require new light devices and, above all, new photosensitive materials. The present lecture is mainly concerned with an overview of the different possibilities for the photoinitiation step of light induced polymerization reactions and a general discussion on key concepts correlating the excited state reactivity and the structure of the photoinitiators.
Chemistry and reactivity of photoinitiators: scope and expectations