The Effect of Tb and Sm Ions on the Photochromic Behavior of Two Spiropyrans of Benzoxazine Series in Solution

Table 1

The experimental values of absorption maxima of SP and its open form (λ_SP, λ_open), SP ring opening rate constant (𝑘₁), thermal open form ring closure rate constant (𝑘₋₁), equilibrium constant of the reversible reaction (𝐾_𝑒), relaxation time of open form (τ_open-SP), and colorability in DMF at 295 ± 1K. Error limits of the kinetics parameters are in the order of about 5%.

Compound	λSP(nm)	λopen(nm)	𝑘−1×10^3 (min^−1)	𝑘1×10^3 (min^−1)	τopen-SP (min)	𝐾𝑒	Colorability M^−1cm^−1× 10^−2
SP(I)	276	409	3.16	192	316	60	7.36
	370
SP(II)	276	404	7.96	529	125	66	1.30
	370