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Thermal and optical properties of copolymers of 1-adamantyl methacrylate (AdMA) and styrene (St) prepared by free radical polymerization in the bulk are investigated. The copolymer forms an azeotrope when the composition is AdMA/St = 55/45 mol%. The glass transition temperature and decomposition temperature of the azeotropic copolymer are 170 and ca 340 °C, respectively. The refractive index increases nonlinearly with St content from 1.522 to 1.591. The light scattering loss at 633 nm is 28.1 dB km−1, which is less than half of that of polystyrene. The total optical loss including molecular vibrational absorption, which is evaluated using a copolymer-based optical fiber, is 292-645 dB km−1 at 500-700 nm. These values correspond to transmittances of 86-93% for a 1 m optical path length. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

To study the effects of fluorine substituent of polystyrene (PSt) on gradient-index fiber-optic properties, a poly(para-fluorostyrene) (P(p-FSt))-based graded-index plastic optical fiber (GI POF) is fabricated, and its properties are compared with those of a PSt-based GI POF. The para-fluorine substitution positively affects the glass transition temperature ( T g ) of the core, wavelength dispersion of the optimum refractive index profile, bandwidth, and attenuation. The core T g of the P(p-FSt)-based GI POF is 88 °C, which is higher than that of the PSt-based GI POF by 9 °C when both fibers have an identical numerical aperture (NA = 0.2). The optimum refractive index profile coefficient for the P(p-FSt)-based GI POF varies from 2.2 to 2.1 in the 600–800 nm range, whereas that for the PSt-based GI POF varies from 2.6 to 2.3 in the same wavelength region. The bandwidth of the P(p-FSt)-based GI POF is intrinsically higher than that of PSt-based GI POF. Moreover, the fiber attenuation of the P(p-FSt)-based GI POF was significantly smaller than that of the PSt-based GI POF over the source wavelength range. Our study demonstrates that P(p-FSt) has favorable properties as a GI POF base material. [ABSTRACT FROM AUTHOR]

Abstract: As a novel base material for low-loss graded index plastic optical fibers (GI POFs) in gigabit home networks, a copolymer of methyl methacrylate (MMA) and pentafluorophenyl methacrylate (PFPMA) was prepared and its thermal and optical properties were investigated. When the PFPMA content in the monomer feed was 0–50mol%, both the glass transition temperature (T g) and the decomposition temperature of the copolymer were higher than that for PMMA, which is the base material for many commercially available POFs. The transmittance of the copolymer was also found to be higher than that of PMMA since it has fewer C–H bonds per unit volume. As the core material of GI POFs, MMA-co-PFPMA (65/35mol%), which had the highest T g of 118°C was utilized. A low-loss GI POF with an attenuation of 172–185dB/km at the emission wavelengths of a high-speed light source (670–680nm) was successfully obtained for the first time. [Copyright &y& Elsevier]

Graded index plastic optical fibers (GI POF) based on the copolymer of 2,3,5,6-tetrafluorophenyl methacrylate (TFPMA) and methyl methacrylate (MMA) were prepared. The copolymers of 10 wt% and 20 wt% of TFPMA with MMA were prepared in bulk using di- tert-butyl peroxide as the radical initiator at 90-120°C for 48 hr. The glass transition temperatures ( Tg) of the copolymers were 115 and 118°C, and the refractive indexes were 1.4912 and 1.4901 at 589 nm, respectively. The transmittances of the copolymers were a slightly higher than that of pure PMMA. Copolymer tubes (diameter 18 mm, length 600 mm) were prepared by the copolymerization of TFPMA (10 and 20 wt%) with MMA (90 and 80 wt%) as the cladding of the optical fiber. In order to prepare GI POF based on these copolymers, a high refractive index compound, diphenyl sulfide (DPS) $\left( {n_{\rm D}^{20} \, = \,1.6330} \right)$, was added to the mixture of the monomers in the tube (as a core material) and then copolymerized by an interfacial gel polymerization technique. The material dispersion and optimum index exponent g were calculated and found to be very close to that of GI POF prepared from pure PMMA. The obtained copolymer preforms were drawn by heating at 220-250°C with controlling of drawing velocity. The resulting fiber diameter was 0.75 mm and the length was 50-150 m. The attenuation spectra of the fibers were measured and found to be similar to GI POF prepared using pure PMMA. The results indicate that the core material of GI POF can be prepared by a copolymer system in which the refractive indexes of homopolymers are very close to each other and the monomers yield a random copolymer. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]