I froze some mint, but when i thaw it, its really dark almost black?

i cut back my mint the other day and got about a brown grocery bag full. i thought it would be a good idea to rinse it and let it dry then freeze it. well, i took a bag out last night and after it thawed its really dark almost black in color. is this ok? if not, any other suggestions? i want it to be as fresh as i can possibly have it so drying is not an option.