A method to determine the orientation distribution function of montmorillonite clay in nylon 6 nanocomposite films by a combination of infrared (FTIR) trichroic analysis and transmission electron microscopy (TEM) image analysis is described. The structural absorbance of the nanoclay Si-O vibrations was obtained by the sample tilting method described by Schmidt [Schmidt PG. J Polym Sci: Part A 1963;1: 1271 12921. A nonlinear least squares regression was performed to extract the absorbance of individual peaks. The montmorillonite clay orientation in spun cast nylon 6 films can be described by a Gaussian function having a standard deviation of 15degrees i.e. 95% of the clay platelets are tilted at an angle of within +/- 30degrees of the plane of the film. The transition dipole moment angles of the 1018 and 1046 cm(-1) clay vibrations are determined to be 18 and 16degrees relative to the clay surface, respectively. The orientation of nylon 6 in the nanocomposite was also investigated based on the NH stretching mode. The NH bonds are found to be less preferentially oriented along the plane of the film surface compared to pure nylon 6 film. (C) 2004 Elsevier Ltd. All rights reserved.