Glass is a substance that is very useful but that shatters easily, so glass in a dream can represent something important in your life that you are in danger of hurting or destroying.
A dream about a glass object can be a message that you need to pay attention to what is important in your life and that you need to reconsider your priorities.
If you dream that you accidentally break an object made of glass, it can be a warning that you are already hurting something or someone that is important to you.
A glass window is something that is itself difficult to see, but that acts as a barrier, preventing you from reaching the things beyond that transparent barrier that you can’t see.
Therefore, glass in a dream can represent something that has not been apparent to you, but that has been preventing you from reaching a goal.
A dream of breaking through a glass window is a sign that you are breaking free from restrictions in order to move forward toward a new phase in your life.