I have a small clear acrylic plastic container, roughly spherical and about 1.5 cubic inches in volume, with a 1/4-inch wall and thinning to about 2mm at the top edge (near the 1-inch diameter lip). I want to put some objects in it and fill it with clear resin and a small amount of tinting (glow-in-the-dark powder) so that the objects and glow can be seen through the clear container. What resin or other substance (silicone, etc.) can I use for this?
Some concerns, in rough order of importance:
1) Shrinkage. I want the resin to entirely fill the container once it has cured, with no gaps. If it shrinks and pulls away from the edges this would be bad.
2) Crazing or other chemical reactions with acrylic. I have heard that polyester resin (or maybe just the hardening catalyst?) reacts with acrylic plastic to cause crazing (tiny cracks) on the acrylic surface. This would be bad in my application. I am not sure if epoxy or other resins have this problem.
3) Ultraviolet transparency. Ideally I would like the resin to be completely transparent to ultraviolet, although some translucency (browning?) may be OK. (The glow-in-the-dark powder needs to charge.)
4) Transparency. I would like it to be as clear as practical. It is going to become somewhat translucent when I add the glow-in-the dark powder, so I would prefer to at least start fairly clear.
I would appreciate suggestions as to a resin or process that could satisfy these criteria. Thanks!