CG Abstract Material Description (BRDF) which maps into OpenGL

We are searching for an abstract material description which can fully exploit features of a modern raytracer (we are using Intel Embree) using for example BRDFs. This material description should than also be mapped into Phong materials used in OpenGL. We have an existing implementation of Phong Materials in OpenGL but want to abstract the material so that it can description so that it can be fully utilized by an raytracer. We are using JavaScript for the implementation. The developer should have existing knowledge of raytracing, BRDFs, Phong materials in Raytracing and in OpenGL (and the theories behind all of these).