Dyeing clear glass microbeads

I need to dye clear glass microbeads (soda-lime glass). How can I color them without changing their collision properties?
I tried to use enamel paint but the microbeads tend to stick to each other and to glass slabs. Any help appreciated.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.