Covalent adaptable networks (CANs) offer a compelling combination of mechanical robustness, structural stability, and reprocessability, positioning them as sustainable alternatives to traditional thermosets and thermoplastics in emerging fields. Extensions of classical theories, such as the affine network model, associate elasticity to the density of active network strands but often oversimplify transient networks by assuming that newly formed network chains are force-free and neglecting conformational changes during bond reactions. These limitations hinder a comprehensive understanding of CAN mechanics. In the present study, we develop a theoretical framework that couples macroscopic elasticity with microscopic bond kinetics and conformational transitions. Using a light-responsive CAN as a model system, we demonstrate how illumination modulates network connectivity, reaction dynamics, and stress relaxation. We identify conformation switch (CS) during bond reactions as a key microscopic contributor that plays a critical role in tensile recovery and mechanical tuning. Our model, validated against stress relaxation experiments under periodic light irradiation, reveals that CS introduces an additional mechanism of mechanical adaptation overlooked in prior models. Furthermore, we explore how molecular characteristics, such as molecular weight and functionality of macromers, impact the macroscopic mechanical response. These results provide mechanistic insights and design principles for responsive and adaptive materials.
