The central aspect of this work was to develop physics-based and chemistry motivated constitutive frameworks to predict the responses of polymers and elastomers under thermo-oxidation and photo-oxidation processes. We denote by physics- and chemistry-based constitutive frameworks those constitutive relationships whose material properties are micromechanically motivated, and whose evolution due to thermo-chemo-mechanical aging can be expressed entirely in terms of physio-chemical quantities that can be measured using chemical characterization tests. This is desirable in comparison to existing approaches which have traditionally relied on simple fitting of the constitutive equations to the already obtained experimental mechanical measurements on aged material. Doing so renders the constitutive equations essentially a fitting algorithm that can only describe the particular scenario upon which the calibration was performed. In contrast, purely physio-chemically-based evolution functions of the material properties, based on network evolution, are desirable to eliminate the need for fitting parameters. The objective was to bypass the need for these traditional phenomenologically based expressions for the evolution of the material properties which inevitably give rise to several fitting variables that do not necessarily bear a physical meaning.