Spectral properties of 3-hydroxyflavone embedded in polysiloxane: Effects of the polymerization method

Abstract The optical properties of 3-hydroxyflavone (3HF) embedded in siloxane matrices obtained through different synthetic procedures are herein presented for the first time. In this work, polysiloxanes derived from Room Temperature Vulcanization (RTV) by (i) Pt catalyzed hydrosilylation, (ii) tin catalyzed polycondensation and (iii) moisture induced polycondensation are loaded with 3HF molecule both by direct dissolution of 3HF within the siloxane precursors and by swelling of the bare siloxanes from 3HF acetone solutions. The structural changes of the 3HF molecule as the cross-linking reaction proceeds are monitored by FT-IR spectroscopy, whereas the evolution of the optical features of the dye molecule and in particular of the Excited State Intramolecular Proton Transfer (ESIPT) mechanism in the course of RTV is observed by fluorescence and excitation spectroscopy.