Previously, we have reported the first demonstration of holographic two-photon induced photopolymerization (H-TPIP) in the construction of transmission holograms. This technique relies on the coupling of a two-photon absorbing chromophore and a photocurable optical resin. Several different systems have been successfully explored; all involving varied reaction pathways. Since the initial report, we have also expanded this technique to reflection holograms and some bulk structures. While the applications for this process are widely ranging, the underlying physical mechanisms still require a great deal of investigation. In this work, we report on some of the photo-physical mechanisms involved in the H-TPIP technique. Specifically, we will report on evidence for mass-transport phenomena, and the role of localized thermal loading. We also discuss a preliminary model, which examines the coupling between the chromophore's excited state population, initiation of the polymerization reaction, and localized thermal deposition.