An elongated light-guiding element includes opposed incident and emission ends between which light propagates by total internal reflection. The light-guiding element includes a glass core with first and second glass core ends and a glass-core outer surface. A non-glass polymeric optical layer extends over at least a portion of the length of the glass core and is disposed peripherally thereabout. The optical layer has first and second optical-layer ends and an optical-layer exterior surface extending between the first and second optical-layer ends. The glass core and the polymeric optical layer exhibit indices of refraction that are matched to one another as closely as practicable such that the combination of the glass core and the optical layer exhibits optical properties similar to those that would be exhibited by an optical element of similar shape and dimensions fabricated from a single, continuous mass of optical material having a refractive index equal to the that of the glass core material.