The fluorescence polarization method,recently developed for the evaluation of the preferential orientation of fluorescent dyes adsorbed in layered materials[F.L o´ pez Arbeloa,V.Mart´ınez Mart´ınez, J.
Photochem. Photobiol.A:Chem.181(2006)44],is readapted to improve its application.Fluorescence
polarization was previously obtained by recording the emission intensity for two orthogonal orientations of the emission polarizer(i.e.,thehorizontalandverticalpolarizedlight) after excitation
with vertical or horizontal polarized light.In the method proposed in this work,samples are excited with unpolarized light,reducing the polarization effect of the excitation light scattering at those emission wavelengths close to the excitation wavelength.Moreover,the present method decreases the
effect of the orientation of othernon-fluorescent species present in the system,which are active in the
excitation process.Consequently,the new method is more simple,precise and sensitive.It is applied to
evaluate the orientation of rhodamine 6G dye adsorbed in ordered laponite clay films with low and
moderated dye loadings.