To understand the origin of complex physical behaviors in natural and synthetic polymers, conventional mechanical measurements are inadequate, because they merely provide a macroscopic relation between stress and deformation. In recent years, spectacular developments in experimental techniques and mechanochemistry have enabled access to real time micro-structural changes of polymeric materials, thereby considerably enhancing the knowledge of polymer physics. In this project, external radiation (scattering of X-rays) and internal radiation (mechanochemistry-induced visible fluorescence) based measurement techniques will be coupled with computational mechanics to investigate the generalized mechanics of polymers -- especially, double-network hydrogels. While the former measurement technique can detect spatial distribution of damage domains in polymeric samples, the latter one allows for the direct connection between the intensity of emitted light and the damage evolution in double-network hydrogels. These two approaches provide sufficient ingredients for constructing a micromechanical damage model for double-network hydrogels. Here, the ill-posedness induced in computation of continuum damage model is treated by a physically-based regularization theory. Then, numerical results will be validated by comprehensive experimental setups using confocal laser scanning microscopy (CLSM) and small-angle X-ray scattering (SAXS).