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Current optical polymeric materials for advanced fiber laser development are susceptible to degradation due to the heat generated in high power usage. A suitable replacement light stripping material was explored to overcome this problem by examining optical and physical properties such as transmission/absorption, refractive index, thermal conductivity, and thermal stability. The synthesis and characterization of two new polyurea/silica ORMOSILs (ORganically MOdified SILicates) suitable for high temperature (up to 300 °C) optical applications are reported herein. A one-pot, room temperature synthesis is based upon commercially available bis-isocyanates and an amino-silane. These materials exhibit the combined traits of both glass and polymer by displaying optical clarity over a wide range of wavelengths stretching from the edge of the UV (250 nm) to well into the NIR (2,000 nm), refractive indices in the visible spectrum (n = 1.50–1.63), thermal conductivities of 0.26 ± 0.09 W/mK (ORMOSIL-A) and 0.27 ± 0.07 W/mK (ORMOSIL-B), and thermal stabilities up to 300 °C. The hybrid materials were found to be easily processed into films but thick casts (>2 mm) were subject to increased rates of cracking and longer curing times. Although this is typical of sol–gel chemistries, the organic constituents of ORMOSILs reduce this effect as compared to purely inorganic sol–gels. The effect of thermal aging on the materials’ properties will also be presented as well as a comparison of these materials and the current state of the art light stripping material.

A carboxylated polysulfone (C‐PSF) was reacted with 3‐(glycidoxypropyl)trimethoxysilane (GPS) in a sol–gel reaction to form hybrid networks. Specifically, GPS was grafted to the C‐PSF chains at their epoxy ends by ring‐opening reactions and then the methoxy silane groups at their other ends were crosslinked through the usual hydrolysis and condensation reactions. These C‐PSF/GPS cross‐linked binary networks are of interest in their own right, but this type of network was also used in the incorporation of polybenzimidazole (PBI) rigid‐rod polymer to form a C‐PSF/PBI/GPS ternary composite. In this case, the network structures obtained by carrying out the same reaction in the presence of PBI chains successfully suppressed their undesirable segregation within the composite. The transparencies of the preparative solutions and the dried films indicated that the dispersion of PBI was maintained in these environments, presumably at the nano‐ or molecular level. The ternary composites were characterized u...

Differential scanning calorimetry has been used to investigate the structural relaxation in a bulk metallic glass designated Vit 4. Results indicate that Vit 4 has a broad glass transition region with a glass transition temperature of approximately 621 K and an activation enthalpy of 834 kJ/mol. Despite the broad transition region, Wunderlich’s model suggests that structural relaxation in Vit 4 involves the cooperative motion of a single bead. The relaxation behavior was well described by the Tool–Narayanaswamy equation, with x and β values not significantly different from other glass formers. The dynamic and thermodynamic fragility of Vit 4 is compared with other glasses.