A poly(ester urethane) multiblock copolymer containing poly(epsilon-caprolactone) glycol (PCL) soft segments gives ring-banded spherulite as crystallized from its melted film. Analysis based on polarized light microscopy and atomic force microcopy revealed that the ring-banded structures consist of alternate convex and concave bands as a consequence of rhythmic growth. These convex and concave bands, which are composed of flat-on and edge-on lamellae, show layered terrace-like and fibrillar morphology, respectively. The chain orientation and composition distribution in the ring-banded spherulites were further investigated using FTIR imaging. The convex bands are mainly PCL-rich domains with perpendicular chain orientation to the substrate, and the concave bands are urethane-rich domains, where the PCL chains are perpendicular to the radial growth directions of the spherulite but parallel to the film plane. The formation of different orientations in the convex and concave bands is attributed to the rhythmic growth behavior for the copolymers with composition distribution along the chains. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 541-547, 2010