Sure, when it is mixed, even when it is poured into the containers, it forms air in the mix. The more you mix it, the more are gets in. When you pour the clear mix into a mold, the air forms bubbles that hurt the clarity, if if bad enough, the strength.
There are two ways to combat the air. One is to degass, the other to crush the bubbles.
To degass the mix you put it into a vacuum chamber, draw out the air pressure to near zero, let the air bubble out. Depending on the material, it can take 60 seconds to three minutes.
To crush the bubbles, you can put the mix into your molds, then put the molds in a pressure chamber and pressure to 60 PSI or more and let the mix cure.
I tend to go with the vacuum chamber, let it degass, then pour into the mold slowly so it does not add air back in.
I have a video (pretty shaky but OK) that I can email you, but it is to big to attach here. PM me your email and I can send it to you.