Encapsulation of photochromic compounds possessing positive and negative photochromism

•Encapsulated photochromic compounds were obtained by one-step ultrasound approach.•Positive photochromic effects were demonstrated for encapsulated spiropyrans.•Negative photochromism was achieved by encapsulation of spiropyrans with Mg2+ ions.•Reversibility of photochromic reactions was proved by the spectral-kinetic method. The photochromic compounds are of great interest due to their unique ability to undergo reversible intramolecular transformations under the influence of light, accompanied by changes in the absorption spectrum. The aim of the present work is the development of the polymer system for encapsulation of the photochromic compounds with maintaining the photochromic properties. The core–shell capsules were produced by a versatile one-step ultrasound treatment. The capsules possess positive or negative photochromic effects depending on the nature of the photochromic systems to be encapsulated. The capsules are demonstrated a noticeable photochromic reaction, which could find a broad application in various fields including information and biomedical technologies.