No it doesnt work, because rotom doesnt evolve. With the same logic this could work with giratina, shaymin, deoxys. But it doesnt.
''A mysterious evolutionary lump. When held, it raises the Defense and Sp. Def of a Pokιmon that can still evolve.''
Information taken from Serebii. That can still evolve. Rotom, giratina, deoxys, shaymin dont evolve they change forms, so eviolite doesnt work.
