A series of photochromic polymers were prepared by forming inclusion complexes of various spiropyrans (SPs) in the cyclodextrin cavities of the beta-cyclodextrin polymer (CDP). Experimental and calculation results demonstrate that the hydrophobic beta-CD cavities can encapsulate the studied SPs from an aqueous solution and form 1:2 SP/beta-CD inclusion complexes. The complexes undergo reversible photoinduced isomerization from a colorless closed form with absorption maxima (lambda(expt)) at 297-359 nm to a colored open-form photomerocyanines (PMs) with absorption maxima at 547-618 nm. For the less polar closed-form SPs, the beta-CD cavity behaves similarly to toluene, providing a hydrophobic environment, and thus the lambda(expt) of the inclusion complexes of SPs with the in CDP is increased compared with that of ethanol solutions of the SPs. However, the structure effects from the steric hindrance of the beta-CD cavity reduce the energy gap of excitation and further increase the lambda(expt) of SPs. For zwitterionic open-form PMs, the hydroxyl groups, laced on the rims of beta-CD, act similarly to ethanol. The interaction effects from the hydroxyl groups simultaneously lower the ground- and excited-state energy of the SPs. The competing effects between the structure and interaction factors cause changes in the lambda(expt) of SPs. (C) 2012 Elsevier Ky. All rights reserved.