Polarimetry
Polarimetry is a method in plastic morphology that is used to make stresses in transparent plastic parts visible. This is achieved through the use of polarised light, which makes it possible to detect stress distributions in the material that would not be visible to the naked eye.
Polarimetry uses special devices that consist of two main components: a polariser at the light source and a rotatable polariser at the analyser. The polariser at the light source ensures that the light passing through the plastic part is polarised. This means that the light waves are aligned in a single plane. When this polarised light hits the plastic part, the internal stresses in the material become visible, as they refract and scatter the light in different ways.