Theoretical and Experimental Study of New Photochromic Bis-Spiropyrans with Hydroxyethyl and Carboxyethyl Substituents

Table 3

Spectral and kinetic properties of the bis-spiropyrans (2a–c) (𝜆^𝐴_max,𝜀(𝜆^𝐴_max) are parameters of the absorption spectra before irradiation (i.e., characteristics of the spirocyclic isomers); 𝜆^𝐵_max is positions of the longwave maxima generated under irradiation; 𝜏^𝐵₂₀ is lifetime of the photoinduced forms).

Compound	𝜆^𝐴max, nm	𝜀(𝜆^𝐴max), M^−1 cm^−1	𝜆^𝐵max, nm	𝜏^𝐵20, s	𝜆^𝐵2max, nm
	248; Sh 274; Sh 290; Sh 325; Sh 340	33180; 23180; 18970; 2840; 1870	603; 415	65.9	507
	331; 340	3370; 2920	596	349; 46	—
	Sh 326; 341	3270; 2310	613; 412	17.6	504