Probing molecular order in zeolite L inclusion compounds using two-photon fluorescence polarimetric microscopy.

We investigate the local static molecular orientational behavior in zeolite L inclusion compounds by polarimetric two-photon fluorescence microscopy. This technique, based on the polarized read-out of the signal under a tunable incident polarization state, provides refined information on molecular disorder that is not achievable using traditional fluorescence anisotropy. Moreover, the polarimetric microscopy imaging scheme permits a spatial investigation of possible heterogeneities, with a submicrometric resolution. The study performed on different fluorescent molecules inserted in zeolite L channels evidence a degree of disorder for either small or flexible structures.