The conformation of the single polymer chain in uniaxially stretched poly(methyl methacrylate) (PMMA) films was studied by scanning near-field optical microscopy (SNOM), which enabled us to observe the elongated conformation of each polymer chain embedded in the film. The conformation of the individual PMMA chains was quantitatively evaluated from the fluorescence intensity distribution. Observation of films with different strains showed that the microscopic strain of the single chain was smaller than the macroscopic strain (6) of the film. Especially at the later stage of the deformation (epsilon > 1.5), the PMMA chain was not stretched with the increase in the macroscopic elongation of the film, suggesting the presence of slipping of polymer chain on the course of stretching. (c) 2007 Elsevier Ltd. All rights reserved.