A crosslinked polymer based solid electrolyte prototype material –poly(propylene glycol) diacrylate– is studied using the reactive molecular dynamics force field ReaxFF. The focus of the study is the evaluation of the effects of equilibration and added plasticizer (ethylene carbonate) or anion components on Li ion transport properties in the solid electrolyte. The study includes initial evaluation of the force field, including bond dissociation characteristics, relevant for material failure, and elastic properties at room temperature, relevant for the structural application purpose. All considered systems indicate enhancement of Li ion diffusivity with respect to the 1 atm equilibrated system without additives/anions. Based on Li-O radial distribution function and integral radial distribution function comparisons, this is attributed to differences in Li solvation structure and related plastification, complexation and solvent exchange mechanisms.