The invention discloses photochromic microspheres with excellent
thermal stability and a preparation method of the photochromic microspheres. The method comprises following steps: 1), a
polymer or
oligomer, a photochromic compound, an
antioxidant, an
ultraviolet absorbent and a sensitizer are swollen in an oil-soluble
solvent with low
boiling point; 2), after being heated to certain temperature and stirred and dissolved into uniform
oil phase, a mixture is added to an
aqueous solution containing an emulsifier and a co-emulsifier, and an oil-in-water type stable
emulsion with
emulsion droplet particle size range being 10 nm-1000 mu m is obtained through shearing emulsification; 3), the temperature of the
emulsion system is increased and kept for a period of time, the low-boiling-point
solvent in emulsion droplets is completely volatilized,
polymer microspheres with uniformly dispersed photochromic molecules are obtained, and dry
polymer microsphere powder with the uniformly dispersed photochromic molecules can also be directly prepared from the emulsion with a
spray drying process. The microspheres prepared with the method are of a homogeneous
solid structure, excellent in
mechanical property and good in
heat stability and have great application prospect in the fields of anti-counterfeiting, plastic products, fabric clothing, chemical printing and
dyeing and the like.