This question is poorly constructed. I think you are asking, "Does an elementary decay?" Yes, elementary particles change into other elementary particles all the time, some more quickly than others. But they must still obey conservation laws as they do so, so an electron could not just loose its spin. Elementary particles are, by definition, elementary. You can not have a red electron or a blue electron or a minty electron, a tired electron, or a dead electron. All photons in the same quantum state are identical. The only way to intrinsically change an electron is to transform it into something else.
Now, the part of entropy that deals with an increase of disorder is a statistical law that applies large numbers of particles, so it does not directly apply to a single elementary particle.