Yes—a polarizing filter can help reduce reflections from glass, so it may improve the view through a window. However, it also cuts light, which can hurt image quality, especially for security cameras in lower light.

A more reliable first step is to block stray indoor light from reaching the window. A long hood or shroud that fits flush against the glass is often better, because it reduces reflections and glare without costing light. Even a simple black cardboard tunnel can work. Placing the lens very close to, or directly against, the window can also reduce visible reflections.

One caution: any extra glass in front of the lens, including a filter, can introduce flare or additional reflections. If the window is double-glazed, a hood against the inside pane may not eliminate every reflection, and a polarizer might still help in that case.

So: start with a tight light-blocking hood and camera placement close to the glass; add a polarizer only if reflections remain and the light loss is acceptable.