Several studies of the time varying photon absorption effects, which occur during the photo-initiation process in photopolymer materials, have been presented. Three primary mechanisms have been identified: (i) the dye absorption, (ii) recovery, and (iii) bleaching. Based on an analysis of these mechanisms, the production of primary radicals can be physically described and modelled. In free radical photo-polymerization systems, the excited dye molecules induce the production of the primary radicals, R^•, which is a key factor in determining how much monomer is polymerized. This, in turn, is closely related to the refractive index modulation formed during holographic recording. In this article, we overcome the complexicy of estimating the rate constant of intersystem crossing, k_st, in going from the excited singlet state dye to the excited triplet state dye, by introducing k_aS and k_aT into the model, which are the rate constant of photon absorption from ground state to singlet state and triplet state respectively.

Date Published: 4 May 2012
PDF: 11 pages
Proc. SPIE 8429, Optical Modelling and Design II, 842921 (4 May 2012); doi: 10.1117/12.923120

Published in SPIE Proceedings Vol. 8429:
Optical Modelling and Design II
Frank Wyrowski; John T. Sheridan; Jani Tervo; Youri Meuret, Editor(s)