Amorphous organic photorefractive materials, which are useful for reversible holographic applications such as real‐time optical processing and holographic data storage, have excellent performance but limited self life, often owing to the crystallization of one of the components. A technique is presented for improving the long‐term stability of composites based on poly(N‐vinylcarbazole) that uses mixtures of two isomeric electrooptically active chromophores. The self‐life is shown to be significantly increased and the photorefractive device performance as good as that of the best materials known previously.