Can annihilationbe considered a phase change?

Question

Since phase changes of matter are accompanied by the absorption or release of energy such as a solid to a liquid. Can annihilation be conisedered a type of phase change?

Answer 1

It wouldn't be called a phase change. Water in the gas, liquid, and solid state is still water, with the same chemical composition of H2O. When an electron collides with its antiparticle the positron, they 'annihilate' to release a photon. Generally that photon later decays into an electron and a positron. They aren't really destroyed, but they travel to somewhere else at the speed of light and reappear, perhaps with lower energy.