On the validity of crystallization kinetics parameters derived from the depolarized light intensity (DLI) technique: An experimental study of polyvinylidene fluoride

Although the depolarized light intensity technique has been known for some decades, the time dependence of light intensity does not yet seem to be wel l understood. In this article, devoted to the crystallization kinetics of p olyvinylidene fluoride (PVDF), we present some of the problems associated w ith quantitative analysis. Parameters such as incident light intensity-in c ombination with the detection system-and specimen thickness are shown to dr amatically affect the apparent kinetics. Experiments on single spherulites grown in very thin films can help interpret the intensity-time curve. Our r esults demonstrate that care should be taken when comparison is made betwee n DLI and differential scanning calorimetry. (C) 1999 John Wiley & Sons, In c.