For mechanophore simulations, a gas phase spiropyran molecule, Figure , is employed to act as a truncated mechanophore/polymer system. Atomic forces were calculated with the ReaxFF-LG parametrization. We employ the CoGEF 31 algorithm, with anchored H atoms (cyan in Figure ), using a constrained structural relaxation via energy minimization. Geometry optimization was conducted via the conjugate gradient method with energy and force tolerances of 1 x 10 -4 (unitless) and 1 x 10 -6 kcal/molA, respectively. To better explore the underlying energy landscape and being trapped in a local minimum, we combined CoGEF with MD, performing 10 fs of NVE dynamics between geometry optimizations.