Xl. Li et al., Synthesis and photochromic behaviors of novel bis-spiro-naphthooxazines connected through a phosphoryl group, MOLEC CRYST, 344, 2000, pp. 295-300
A series of novel bis-spironaphthooxazines (3a similar to 3i) and (4) conta
ining a phosphoryl group were synthesized in 70 similar to 91% yield. Their
photochromic behaviors and photostabilty were investigated with the aid of
absorption spectral measurements, showing that they exhibited higher fatig
ue resistance in the coloration and decoloration cycle than that of the par
ent reference compound 1.