No, it can't mean window. It's a specific thing. The word 'looking-glass' can't mean 'window' any more than the word 'mirror' can mean window. They're not synonyms.
However, if you were deliberately trying to make a connection between the two things for symbolic reasons, hinting at an Alice-like moment/analogy, then you could use 'looking-glass' as a simile, or in your description.
For example:
If you said something like "He stood before the looking-glass and watched the children playing on the lawn outside" people are going to be confused and it doesn't really work as a metaphor. It's just clumsy.
But if you said "He stood before the window, its panes glistening in the sunlight like a polished looking-glass, and watched the children playing on the lawn outside" then you could use the looking-glass reference/analogy without sounding as if you'd just used the wrong term.
Or you could also say something like "As he stood at the window, watching the children playing on the lawn outside, he was aware of his own reflection in the panes, as if he were staring through a looking-glass."