To fix pastel paintings or not

This thread is quite old ( 2017 ) but I hope someone can give me some advice.
I am new to Pastels and have framed a few of them under “Anti Reflex Glass” they look OK but the glass seems to dull down the details and seems to subdue the colors somewhat.
After watching a recent Marla Baggetta demo where she highly recommends using Krylon " Fine Art Fixative" …
I’m not sure if she still mounts them under glass, or, just leaves them that way with the fixative as the final coat and for presentation.
What are you experienced pastelists doing?
Thanks, Eric