Synthesis and optimization of a novel polymer: dye composite (PVA:MV-6B) films for band-stop optical filters

An innovative optical filter of polymer composite based on methyl violet-6B (MV-6B) doped poly(vinyl alcohol) (PVA) films in the concentration range of 0.01 mol.%, 0.04 mol.%. 0.08 mol.% and 0.1 mol.% of MV-6B were fabricated by simple and conventional solution film casting technique. The structural and optical characteristics of the prepared samples have been studied using both X-ray diffraction (XRD) scans, Fourier transform infrared (FT-IR) and UV-vis-NIR spectroscopies. A simple optical set-up has been arranged for the optical limiting measurements using low power He-Ne laser (λ = 632.8 nm). A markedly decrease in the degree of crystallinity of the PVA film due to MV-6B doping was observed. Doping of MV-6B to the PVA polymer chains strongly affects the optical absorption spectrum of the films. The optical transmission spectra measurements for PVA film doped with 0.1 mol.% MV-6B show a highly absorption in UV optical range (200 nm–350 nm) and complete blocking in broad visible range (500 nm–625 nm). Three optical band gaps corresponding to the PVA polymer and the (PVA:MV-6B) composites films were observed. The optical limiting features showed a significant decrease in the laser output power by increasing MV-6B concentration in the PVA matrix.