Additive and free‐volume effects on the refractive index of a thiol‐ene polymer network

Abstract

A series of hard, transparent, thermoset polymer samples containing tetravinylsilane (TVS) and 1,3‐benzenedithiol (BDT) with varying loadings of zirconium oxide clusters Zr6(OH)4O4(OMc)12 (ZOC) were synthesized. Resulting polymers exhibited a higher refractive index (n) than the parent polymer containing only the monomers TVS and BDT. The refractive index reached a maximum value of 1.711 at a ZOC loading of 3 wt% and then decreased as the ZOC concentration in the polymer matrix increased. The refractive index of ZOC was determined to be 1.540 using the Becke line method. Because the refractive index of ZOC is lower than that of the TVS–BDT polymer matrix, the finding that the incorporation of small quantities of ZOC can increase the refractive index of the TVS–BDT polymer composite was unexpected and is accounted for by the effects of ZOC on the packing efficiency of the composite.

Improving performance oftwo‐stagephotopolymers for volume holographic recording by fluorinatedepoxy‐amine cross‐linkedmatrices

“…[5][6][7][8] Many kinds of cross-linked host matrices have been reported, which are a mixture of at least two active substances, such as epoxy-amine, epoxy-thiol, isocyanate-alcohol, orthoester-anhydride, and thiol-allyl. [9][10][11][12][13][14] Compared with other cross-linked systems, epoxy-amine has excellent mechanical properties and low volume shrinkage, which is very important for millimeter-thick media in holographic data storage. However, high cross-linking density of epoxyamine matrices sacrificed the diffusivity of monomers, resulting in blurry grating fringes of allyl/epoxy-amine-based photopolymers, which limited their further applications.…”