Can curtain brackets be glued to the rim of the windows?

I'm not sure if glue would be strong enough to hold weight of curtains. If you use for light weight curtains it may work. If you are using drapes which are heavy you should stick with the nails or screws.

If you are in an apartment and worry about your deposit...you can fill holes with plain white toothpaste.

You would be better off using Command Hooks or Command Strips. Just make sure not to exceed the weight limit.

yes you can just depends what kind of glue you use if it will stick/stay/hold weight of curtains

Better than glueing are the brackets that go over the upper corners of your trim. There are brackets that hold standard curtain rods (double or single) and those that will hold a bar. They tap into place with a hammer a do not damage your trim.