We have window films. This is a thin layer of film which is pasted on the glass to serve various purposes.
1. Privacy. Frosted films makes the glass obscure, you can't see through but it allow light light to see through
2. Oneway they allow you to see outside but from out you cannot be seen.
3. Block out. Blocks our light and visibility
4. Solar protection
5. Antishatter films. Once the glass breaks it doesn't shatter.