Environmentally stable NIR‐absorbing window

PurposeThe purpose of this paper is to develop environmentally stable near‐infrared (NIR)‐absorbing windows by blending an NIR‐absorbing dye and a thermally‐crosslinkable polymer.Design/methodology/approachTo enhance the environmental stability of the NIR‐absorbing window, a poly(vinyl phenol‐co‐methyl methacrylate) (poly(VP‐co‐MMA)) prepolymer and a poly(melamine‐co‐formaldehyde) (PMF) cross‐linking agent were mixed, and thermal crosslinking was performed under mild conditions (100°C).FindingsThe resistance of the crosslinked hybrid films to heat, humidity, and ultraviolet radiation damage improved dramatically relative to the pristine NIR‐absorbing dye. The improved environmental stability of the crosslinked NIR hybrid film resulted from the reduced free volume and restrictions in the molecular thermal dynamic motions of the polymer due to the presence of the crosslinked network surrounding the NIR‐absorbing dye molecules.Originality/valueThe methods provided a novel, simple, and practical solution to improving environmentally stability of NIR‐absorbing window.