Gelation process has been investigated by using light scattering techniques in recent years. We measured both of rotational and translational motions of fluorescent probes during gelation process. The measurements were performed after the temperature quenched at 30 degrees C. As the results, rotational diffusion coefficient of fluorescein was decreased after 6.0 x 10(4) s and energy transfer rate was reduced after 2.0 x 10(4) s. We sorted the gelation. process into the following three parts, (I) pre-gelation, (II) reduction of translational diffusion (aging), and (III) reduction of rotational diffusion with saturating translational diffusion (post-gelation). The time scale of the process was completely different from the results of other methods. (c) 2006 Elsevier B.V. All rights reserved.