It can only be cured by ultraviolet radiation, that is, the photosensitizer in the shadowless adhesive will combine with the monomer under ultraviolet radiation. Theoretically, if there is no ultraviolet light source, the shadowless adhesive will hardly cure.
There are two sources of ultraviolet rays: natural sunlight and artificial light sources. The stronger the ultraviolet ray, the faster the curing speed. The general curing time is 10-60 seconds. For natural sunlight, the ultraviolet rays on sunny days will be stronger and the curing speed will be faster.