In order to design and manufacture components that can reliably withstand loading in different environments, the material properties of the components and their changes under the respective environmental influences must be analysed in detail. This study uses the acquired experimental data to determine the chemical changes in the material structure with the focus on thermal ageing of elastomers. The mechanisms of thermal ageing are briefly described, and based on them, a very simple approach to model the ageing behaviour is introduced and the model parameters are identified using commercially available optimisation algorithms. Afterwards, the numerical results are compared with the measured data and the model performance is discussed along with the possible model weak points and their improvements.