Abstract: | A Biolar PI polarizing interference microscope (a Pluta microscope) attached to a special hot stage was used to study the influence of temperature on the dispersion properties of polypropylene fibers with different deniers (6 D and 90 mm, 6 D and 150 mm, and 12 D and 150 mm) over the temperature range of 30–50°C. This study was carried out with a variable‐wavelength interferometry technique. Constant A of Cauchy's dispersion formula and the oscillation and dispersion energies for light vibrating parallel and perpendicularly to the fiber axis were determined at different temperatures. Microinterferograms are given for illustration. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1135–1141, 2005 |