Nanoimprint technology is one of the promising technologies for the next generation of IC industry. On of the drawbacks of nanoimprint is blurring or degradation of the nanoimages due to the relaxation movement of the polymer strings. Poly(methyl methacrylate), PMMA, has been widely used as a photoresist material for nanoscale and microscale fabrications. In this work, we studied the relaxation movement and the glass transition temperature (Tg) of PMMA nanoimages using molecular dynamics simulations. In the simulations, the all-atom force field model is applied the PMMA. The dilatometric technique, the specific volume reported versus the cooling temperature, is employed to evaluate the glass transition temperature. The velocity autocorrelation functions are applied to the description of relaxation movement of PMMA strings.