Exploration of Probing Structure, Fictive Temperature, and Homogeneity of Commercial Glass and Glass Fiber Vibrational Spectroscopic Techniques

Utilizing a set of spectroscopic techniques, i.e., Fourier transform infrared (FT-IR) in transmission (KBr method), attenuated total reflection (ATR) FT-IR, and micro-Raman, and several characterization methods relevant to the commercial production of E-glass fibers for composite reinforcement has been explored, focusing on four major areas: (i) a possible structure alignment in the fibers formed under high tension and high shear rate, (ii) the network structure difference between the skin and core of fibers, (iii) fictive temperature determination, and (iv) glass homogeneity at a nanoscale. The IR band narrowing observed from fiber samples over bulk samples was identified using the ATR method. The use of FT-IR and micro-Raman techniques enables the identification of higher non-bridging oxygen concentration near fiber skin over the core. A relationship between E-glass fictive temperature and the Raman band shift was established to predict the fictive temperature range of commercial fiberglass products. We present here for the first time a demonstration of a new FT-IR procedure for tracking commercial glass inhomogeneity with sensitivity at the nanoscale. The newly proposed glass homogeneity index (GHI) was shown to be closely related to furnace operating temperature upset and correlated with the average fiber break level during the period.