Polymer chains adsorbed on substrates have been observed by atomic force microscopy (AFM); however, observations at high temperatures are not well studied. We observed isolated chains of isotactic and atactic poly (methyl methacrylate) (it-, and at-PMMA) and poly(2-vinyl pyridine) (P2VP) on mica up to 200 degrees C, which is above their bulk glass transition temperature (T-g), and found that isolated chains could be observed even at temperatures much higher than the bulk T-g . The thicknesses of the chains were constant up to 200 degrees C, but the radius of gyration (R-g) of the chains started to decrease at 100 degrees C for it- and at-PMMA and at 150 degrees C for P2VP. In situ AFM observations indicated that the chains started moving at these temperatures, which were approximately 40, 0, and 55 degrees above their bulk T-g . The restricted movements of the isolated chains should provide useful information to understand the surface phenomena of polymers at the molecular level.