Effect of dopant structure on refractive index and glass transition temperature of polymeric fiber-optic materials

Abstract

Graded‐index plastic optical fibers, composed of doped polymers, have advantages over conventional glass optical fibers, but need to be developed further for practical application. Here, a variety of aromatic sulfide dopants were synthesized, and their effects on the refractive indexes and glass transition temperatures (Tg) of poly(methyl methacrylate) and methyl 2‐chloroacrylate/2,2,2‐trichloroethyl methacrylate copolymers were studied. While polymers containing large dopants exhibited relatively high refractive indices, their Tg values were low, making these materials unsuitable for graded‐index plastic optical fiber applications. Six dopants yielded polymers that exhibited higher Tg values than the conventionally used (diphenyl sulfide)‐doped polymer. The dopant dibenzothiophene, in particular, yielded polymers with the highest refractive indexes and Tg values, and polymers containing (phenylthio)benzene dopants also performed well. Copyright © 2013 John Wiley & Sons, Ltd.

Multimodal Interference in Perfluorinated Polymer Optical Fibers: Application to Ultrasensitive Strain and Temperature Sensing

“…Over ∼72 • C, correct measurement was difficult due to the spectral instability. We verified that this behavior is unique to POFs with relatively low glass-transition temperature by demonstrating that the temperature sensitivity of a silica-MMF-based sensor shows almost no change with increasing temperature up to 130 • C. Besides, considering that the phase-transition temperature of polymers can be controlled by adding plasticizers and by copolymerizing/blending different materials [30], we expect that such an ultra-high temperature sensitivity will be achievable not only around 70-80 • C but also around somewhat arbitrary temperature, opening up the way for more useful and practical applications.…”

Light-Generating CdSe/CdS Colloidal Quantum Dot-Doped Plastic Optical Fibers

“…The blank polystyrene was found to possess a T g of (100 ± 2) °C, similar to that measured for the PMMA cladding material (97 ± 2)°C. One particular concern when adding dopants to a polymer matrix is the decrease in T g due to the plasticization effect, whereby the addition of a dopant introduces free volume into the polymer which can promote polymer–diluent interactions in place of polymer–polymer interactions. Additionally, an increase in heat transport within the polymer matrix can occur when semiconductor materials, such as cQDs, are incorporated within the polymer matrix, which can also influence the T g of the composite material .…”

A highly transparent and thermally stable copolymer of 1-adamantyl methacrylate and styrene

“…The prepared copolymer has an AdMA/MMA composition = 30/70 mol% and the refractive index and T g are 1.507 and 155 °C, respectively. For the core, we added 1.00 mol% of DBT, which is one of the most efficient organic compounds for increasing the refractive index of the core polymer with a minimal decrease in T g . This method is used to prepare graded‐index plastic optical fibers (GI POFs) .…”

“…For the core, we added 1.00 mol% of DBT, which is one of the most efficient organic compounds for increasing the refractive index of the core polymer with a minimal decrease in T g . 50,51 This method is used to prepare graded-index plastic optical fibers (GI POFs). 52 The added dopant, whose refractive index is higher than that of the base polymer, diffuses into the cladding layer while the preform is heated in the oven.…”