Light stabilities of a near-infrared-absorbing phosphate ester copper complex and doped resins

The light stabilities of a near-infrared (NIR)-absorbing 2-ethylhexyl phosphate copper complex (EHPC) and resin plates of polymethacrylates containing EHPC were investigated. Light stability was assessed using the ISO 4892 weathering test and a xenon weather meter. EHPC showed high light stability in methyl isobutyl ketone solution. The plate of poly (2-ethylhexyl methacrylate) containing EHPC maintained almost constant transmittance even after irradiation for 1000 h. A resin plate containing poly (dicyclopentanyl methacrylate) as the polymer matrix had a glass transition temperature exceeding 100 °C, which further improved the light stability of the NIR absorption of the copper complex in a resin plate. We developed NIR-absorbing resins with excellent light resistance that are attractive for use as window materials. [Display omitted] •Near-infrared-absorbing resins were investigated as window materials.•Light stabilities of 2-ethylhexyl phosphate copper complex and doped resins were tested.•The copper complex showed high light stability in methyl isobutyl ketone solution.•Resins showed constant transmittance even after irradiation for 1000 h.•Light stability rose using poly (dicyclopentanyl methacrylate) as the polymer matrix.