Optical poling in a crosslinkable polymer system

Efficient optical poling of a crosslinkable polyurethane film, in which a h igh crosslinking density can result, is experimentally investigated and com pared with corona poling. The photoinduced orientation and the crosslinking processes of the chromophores can be performed separately. The heating rat e and the final curing temperature are crucial for the optical poling proce dure. Through thermal curing of the sample, the stability properties of pho toinduced polar order are demonstrated to be dramatically enhanced, especia lly its photostability. It is also shown that corona poling is more effecti ve than optical poling in the case of a crosslinkable thick film.