Precise determination of fictive temperature of silica glass by infrared absorption spectrum

In silica glass, the peak position of infrared absorption spectrum at around 2260 cm−1, which is related to the average of distribution of Si–O–Si bonding angle, is useful for determining frozen-in temperature of glass structure, the so-called fictive temperature. We precisely determined relation between the peak position and fictive temperature up to 1550 °C and found that at fictive temperatures higher than 1400 °C the present relation differs from the relation which has been extrapolated from the previous data at fictive temperatures below 1400 °C. The peak position was found to simply shift to lower wave numbers with raising fictive temperature. This suggests that at fictive temperatures up to about 1600 °C there is no maximum in density, which has been reported to exist at around 1500 °C.