Polyglycolic acid (PGA) (-CH2-COO-)(n) is the first bioresorbable synthetic polymer which is used to make biomedical and pharmaceutical devices. It has a planar zigzag conformation. A comprehensive study of the normal modes and their dispersion in PGA using Urey Bradley force field is being reported. Characteristic features of the dispersion curves have been reported. The heat capacity derived from the dispersion curves via the density-of-states, is in good agreement with the experimental data of Lebedev and Yevstropov. (C) 2004 Elsevier Ltd. All rights reserved.