Is it permissible for a Muslim woman to wear the Christian head covering (consisting of a long dress and a covered head, except for the neck) as a work uniform when teaching children, and then return to wearing her usual Islamic head covering?

A woman is permitted to remove her hijab in front of children if there is no non-mahram man present, provided that these children are not those who are aware of women's 'awrah. If she senses any suspicion from them, she must cover herself in front of them. She is also permitted to wear any clothing that is not specific to disbelieving women or that distinguishes them, such as the attire of nuns.