The aim of this study is to investigate the physical and mechanical properties of polymethyl methacrylate (PMMA) brand Plexiglas GS OZOO due to the absence of stress-strain curves in open databases, such as CAMPUS or MATDAT. In addition, the mantioned databases contain curves only for tension. Stress-strain curves are necessary for more accurate calculation of the stress-strain state of the body. To determine the performance characteristics of the material, the samples were exposed to climatic action. The results of the experimental study of the physical and mechanical properties of the material before/after climatic action are presented. Various models that determine the relationship between stresses and strains (the Menges model, the model based on the logistic function) at temperatures below the glass tran-sition temperature are considered. Numerical values of the model parameters are obtained in accordance with the experimental data. The results of tensile-compressive tests at a constant strain rate from 1 to 10 mm/min (from & = 3.3%/min to 33.33%/min) are compared with the results of tensile-compressive tests of the material at the same rates and room temperature, but after exposing the samples to open air for six months. In addition, the physical and mechanical properties of the material for different ambient temperatures are determined. Stress-strain curves of the material at room temperature are constructed for further use in modeling the stress-strain state of bodies. It is noted that at a deformation of no more than 4%, the Menges model and the model based on the logistic function have proven themselves well. The parameters of both functions for the selected material are presented in the paper. The material has a tendency to embrittlement after climatic aging. The physical and mechanical properties of the material depend on the ambient temperature and the rate of the applied load.