Figure 7.

Absorbance changes at 539 nm for spiropyran (1.0 × 10⁻⁵ mol/L, 298 K, MeCN/ H₂O = 6:4, V/V) with irradiation for 10 min at 365 nm light in the absence of Al³⁺ (blank sample), and in the presence of Al³⁺(Al³⁺) or with other common anions (1 eq). Note: ε_i0 was the absorption intensity at 539 nm with different anions without irradiation in the presence of Al³⁺; ε_i was the absorption intensity at wavelength 539 nm with different anions with irradiation for 10 min at 365 nm in the presence of Al³⁺.