Photo-reactivity of 2,4,6-Tris(benzylthio)-1,3,5-triazines and Accompanying Refractive Index Change

Abstract

The photo-isomerization reaction of 2,4,6-tris(benzylthio)-1,3,5-triazine (TBT) structure was investigated for the first time. Pristine TBT was prepared as the model compound. TBT showed good thermal inertness up to 200 ℃ without any thermal isomerization. The photoreaction of TBT under 254 nm irradiation was investigated with UV/vis and FT-IR spectroscopy using the TBT film in poly(methyl methacrylate) (PMMA) matrix. Detailed analysis of the spectra using density functional theory (DFT) calculation revealed that the single enol-keto isomerization at one benzylthio moiety in TBT dominantly proceeded. The refractive index change along with the photo-isomerization of TBT was evaluated with ellipsometry technique, which showed the refractive index increase of +0.0050 at 633 nm.