Investigation of birefringence of elastically deformed poly(methyl methacrylate)

In the paper we present the results of an experimental investigation of birefringence of a poly(methyl methacrylate) small blocks that are subject to applied mechanical stress. First, the investigated sample is placed between two crossed linear polarizers that effectively polarize visible light within the range from 470 nm to 750 nm, and birefringence of the unloaded sample is measured. After that a load causing elastic deformation is gradually applied to the sample. A white-light source is used for investigation and response of the polarizer-stressed sample-analyzer optical system is detected via optical fiber connected to an optical spectral analyzer. The measured intensity of light transmitted through the optical system is plotted as function of wavelength for various loads. Analysis of the obtained spectra led to the dependences of the normalized intensity of light on the load as well as the birefringence on the load for various wavelengths. The character of the dependences indicates the possibility of utilization the material as a basis for an element of a sensor of pressure, stress, small deformations or for weight measuring.