Photochromic materials exhibit adjustability of their physical parameters to external light stimulus, regarding as an important carrier of optical memory. However, the reversible photochemical reaction in such a medium inhibits the permanent preservation of data. Herein, we propose to embed photochromic tungsten oxide nanoparticles into two-component polymers of polyvinyl alcohol/polyacrylic acid (PVA/PAA). Thermal relaxation of the coloring state is effectively inhibited in the proton-rich polymer matrix, so as to enhance the life, rate and efficiency of photomemory. Moreover, photochromic response boundary extends from near-ultraviolet to green region, realizing colorful hologram reconstruction. This work provides an important strategy for developing broadband, persistent and flexible photonic devices.
