Brillouin Spectroscopy of Oriented Polymers

Abstract

We give a short overview of how to measure orientation-dependent velocities of hypersound by Brillouin spectroscopy, and what kind of data have been attained by this method. The observations in drawn segmented poly(urethane)-elastomers differ from all others: the sound velocity perpendicular to the chains runs through a minimum. At a draw ratio of ∼3.8 a sudden step in the sound velocity indicates a strain-induced structural change.

Key Words:

• Brillouin scattering
• sound velocity
• orientation
• birefringence
• Poisson number
• poly(urethane).