Photochromic properties of the molecule Azure A chloride in polyvinyl alcohol matrix

•Optimization of Azure A chloride.•UV–Vis and IR spectra were recorded and compared with calculated ones.•Charge transfer occur within the molecules.•Preparation of polarizing films.

In the present work, isomerization, photophysical properties and heat conductivity of the substance Azure A chloride (AZAC): 3-amino-7-(dimethlamino)phenothiazin-5-ium chloride under the action of UV radiation in the presence of polyvinyl alcohol (PVA) matrix was studied using the Hartree-Fock (HF) and Density Functional Theory (DFT) methods. The electronic absorption spectra of AZAC in dimethylformamide (DMF) solution and in aqueous medium before and after UV radiation were calculated. The nature of absorption bands of AZAC and its tautomeric prototropic form with the transfer of the electron (AZAC1) in the visible and near UV spectral regions was interpreted. The solvent effect on the absorption spectrum of the AZAC has established. The comparison of measured FTIR, UV–Visible data allowed assignments of major special features of title molecules. The frontier molecular orbital HOMO-LUMO have been also presented that shows the charge transfer interactions taking place within these molecules. The excitation energies for both molecules AZAC and AZAC1 have also been calculated. The experimental as well as theoretical investigations of azure molecule have a close agreement and it gives other important clues about the properties of the system. Anisotropy of thermal conductivity in PVA-films containing AZAC and AZAC1 were also measured.

Graphical abstractThis work relates to a polyfunctional polymer PVA films containing photosensitive photochromic organic dye. It also provide the possibility of combining them to create a heat-polymer film of sun screen materials from a variable (adaptive) light transmittance in the visible region of the spectrum depending on the intensity of solar radiation for use in construction, automotive and aviation industries for glazing large skylights. Study of the anisotropy of thermal conductivity allows you to select the substance which can more easily conduct heat flux and in the meantime not warm when you use the sun.Figure optionsDownload full-size imageDownload as PowerPoint slide