Materials and methods for preparing a modified poly(hexahydrotriazines) (PHTs) polymers and modified polyhemiaminals (PHAs) are provided. A monomer precursor, a photochromic precursor, and a formaldehyde material may be combined to form a photochromic polymer. The photochromic polymer may comprise hexahydrotriazine, hemiaminal, polyhexahydrotriazine, polyhemiaminal, or a combination thereof.