A frozen blade would be quite brittle and would shatter trying to hit armored foes. Enchanted weapons from my knowledge, cast the effect only on the strike, Although Chillrend, and Dragonban has effects, they are unique weapons, and are the exception to the rule.
Enchanted weapons do have a soft "glow" or sheen to them though.
flame enchanted has reddish orange patches i've noticed. also damage stamina has greenish patches. but you can only see the effects on the weapon while they are drawn and easiest immediately after drawing them as it fades.