Figure 8.

a) The dispersion of r‐W₁₈O₄₉ at 0.3 mg mL⁻¹ was irradiated by using a 808 nm laser at a density of 3.5 W cm⁻² for five heating and cooling cycles. b) UV/Vis spectra of r‐W₁₈O₄₉ before (black line) and after (red line) five laser irradiation cycles (808 nm, 3.5 W cm⁻²).