The addition of the first order retardation plate (Figure 10(a)) confirms the tangential arrangement of the polymer chains. The banding occurring in these spherulites indicates slow cooling of the melt allowing the polymer chains to grow out in spirals. This information on thermal history is almost impossible to collect by any other technique. Nucleation in polymer melts can take place as the result of accidental contamination or contact with a nucleating surface and can lead to substantial weakening of the product. Identification of nucleation can be a valuable aid for quality control.