1. Partially crystalline polymers present complex spectra as they are multi-phase materials, in which the molecular motions are more restricted in the crystalline phase than in the amorphous phase. 2. This allows the onset of molecular motion in amorphous polymers to take place at temperatures below the melting temperature of such crystallites. 3. Finally when molecular motion increases to a sufficiently high level, all the chains behave like weak springs the whole time. 4. An increase in the lateral forces in the bulk state will hinder molecular motion and increase T g. 5. As the density increases, the molecular motion in the sample is restricted and T g rises. 6. The onset of molecular motion in a polymer sample is reflected in the behaviour of E and E. 7. This represents a transition point such as T g, T m or some other region where significant molecular motion occurs in the sample. 8. The stop-motion in this case approaches a stoppage of molecular motion itself. |