Gouache has a more difficult time in the medium of precipitated chalk. The even more vulnerable pastels are essentially pure pigment without the protection of a medium. Visible light is in the 400-700 NM band. The damage caused by florescent light can be reduced by the use of UV filtering sleeves. Incandescent light is less damaging.
Halogen is midway between florescent and incandescent.
Closer is worse. Picture lights are definitely a no and can cause differential fading. In addition, the heat created by a light so close to the artwork can cause desiccation. Glass vs. Acrylic - there is no difference in the temperature inside from one or the other. Acrylic is a little better as a thermal insulator.