Blinding sounds like a good alternative for chaining. Either with contacts you can't take our, or with a blindfold or hood locked at the neck (easiest, low-tech solution), you could be left unchained for the night, maybe also for your "free time" after work and during holidays, and obviously for sex. So you could theoritically try to escape but you'd just stumble and walk in circles and feel afraid to cry out for help as you do not know who is around. It would also be mischevious to give you many hours of "free time" but make you pretty useless for that duration so you look forward to being useful again. Oh, this would work well with high heels.