Which photopolymer for printing? I am thinking about building my own DLP 3D printer. I want to know which uv curing resin I should use.

Also, I came across a continuous 3D printing technology where oxygen permeable glass was used to stop the photopolymer toching the glass from hardening so the cured photopolymer wont stick to the glass. What resin additives are used to achive this?
I think you will find that it will be necessary for you to tune your own printer to a specific resin. Even as important, you would expect to have different parameters for different colors of resin, as each will absorb the UV to a different degree.

You haven't provided parameters in your request for which resin to use. You will consider availability and cost of the material you select, as well as the UV light frequency for which a particular product is specified. Temperature range of use is another critical detail.

You'll want to avoid resins for which the manufacturer does not provide specifications of that sort. 

If you pursue this route, you'll find and learn quite a bit.

Regarding the resin additives for non-hardening: I have not seen such a product and I would not be surprised to learn that it is a proprietary substance and as such, a company secret.

There is a recent development of a similar note, a positive one, in my opinion. There is a silicone compound that forum posts have indicated allow the resin to release with minimal or no difficulty and the clarity lasts weeks of use. Current use of Sylgard or the equivalent means frequent re-builds of the vat due to cloudiness of the silicone or tearing of the surface due to excessive stickiness.

Breakable Glass Silicone has developed quite a following on the B9Creator forums for solving (or substantially reducing) those two factors. That alone justifies the immense expense of shipping from Australia, in my opinion.

The easy release of the layers of the model from the surface would mean far more reliability in printing. You should/could consider this product for your project as it removes the requirement for questionable additives.