There are a few methods to measure topology freezing transition temperature (Tv) of vitrimers while the samples are needed to be under external force or additional substances. The novel photonic coatings from the lower photonic crystals (PCs) and the upper vitrimers are fabricated and used to detect Tv of vitrimers. The photonic coatings have photonic stopbands (or structural colors) because of PCs. When photonic coatings are heated, PCs from SiO2 spheres are stable, vitrimers are transformed from solid state to fluid state, light would be easily pierced through vitrimers and reflect off PCs, the intensities of reflection peaks of photonic coatings increase slowly, increase sharply and keep unchanged at three stages. So Tv of vitrimers are directly observed and obtained according to these great changes. The values of Tv of the vitrimers from different synthesis conditions are different. The novel method is simple, intuitive and without external force and additional substances. The photonic coatings also have good toluene-resistance and self-healing property. They have potential applications in detection of Tv of other vitrimers, displays, anti-counterfeiting and automotive coatings.