An alternative method for the determination of the birefringence in stretched polymeric films

In this paper an alternative experimental set-up for the determination of the birefringence of an oriented polymeric film is introduced. The method is based on the determination of the phase difference Gamma (lambda) using three different laser beams with different wavelengths and a tilting compensator. The accuracy of this method is given by the fact that using laser beams, a very restricted area of the sample can be investigated. (C) 2001 Elsevier Science Ltd. All rights reserved.