Abstract
New photochromic materials based on heteropolyoxometallates (HPOM) incorporated into a hybrid organic-inorganic binder were prepared and coated onto polycarbonate (PC) substrates. The hybrid binder was formed through the controlled hydrolysis and condensation of 3-glycidoxypropyl-trimethoxysilane (GPTMS) and bisphenol A (BPA) by the sol–gel technique. The photochromic behavior of the materials was investigated by using ultraviolet-visible (UV-Vis) absorption spectroscopy and color index values. The results indicated that the films were reduced photochemically to yield a blue species under UV irradiation, with the film color changing to deep blue with increasing time, and HPOM and BPA content. The photosensitivity of several films with molybdenum HPOM showed faster coloration and much slower bleaching than the tungsten HPOM. A photochromic mechanism involving electron transfer between the GPTMS matrix with BPA, and PWO is proposed. After UV irradiation, the O–H and $O{=}W$ bonds decomposed gradually and W6 + was reduced gradually with increasing time. The photochromic coatings on PC substrate showed reversible transmittance change before and after UV irradiation, making then efficient light protectors under UV irradiation.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
