Investigation of polymerization rate in an acrylamide-based photopolymer using Raman spectroscopy
Document Type Conference Paper
R. Jallapuram, I. Naydenova, H. J. Byrne, S. Martin, R. G. Howard, V. Toal, “Investigation of polymerization rate in acrylamide-based photopolymer for holographic recording”, SPIE proceedings of Opto-Ireland conference, V.5826, 75-82, 2005.doi:10.1117/12.605416
Diffusion models predict that polymerization and diffusion rates are the key factors that control the dynamics and the final properties of a holographic grating recorded in a photopolymerizable material. Diffusion rates during the initial phase of holographic recording have already been studied and reported. We now report the investigation of the polymerization rate in an acrylamide-based photopolymer using Raman spectroscopy. The polymerization rate constant was estimated by monitoring the intensity of the characteristic Raman peaks at 1284 cm-1 corresponding to the bending mode of CH vinyl bond in acrylamide and 1609 cm-1 corresponding to the carbon-carbon double bond (C=C) in acrylamide as a function of illumination time. The dependence of the residual monomer concentration on the exposure time was fitted using a mono exponential fitting function. The value of the polymerization constant was estimated to be 0.043 s-1mW-0.5. A comparison with some other photopolymer systems reported in the literature reveals that the acrylamide-based photopolymer system is characterized by a faster polymerization rate constant. The results from the present study give significant information for better understanding of the process of holographic recording in acrylamide-based photopolymer system.