This paper discusses the local atomic structure in silicon dioxide films formed by the oxidation of silicon in dry oxygen in a temperature range between 850 and 1150°C. The films grown at 850°C were subjected to rapid thermal annealing (RTA)at temperatures between 800 and 1200°C and for periods of time ranging from 1 to 100 seconds. The local atomic structure has been studied via infrared (IR) spectroscopy and ellipsometry. We discuss the temperature dependence (with respect to both oxidation temperature, and annealing temperature [and time]) of the frequency, v, and linewidth, δv, of the Si-O-Si bond stretching vibration, and the index of refraction, n, at 632.8 nm. We make comparisons with silicon dioxidefilms deposited by remote plasma enhanced chemical vapor deposition (RPECVD) at temperatures between 100 and 400C and subjected to high temperature annealing (850 to 1050°C). We find that the variations in v, δv and n with growth, deposition and annealing can be understood in terms of systematic variations in the magnitude of the bond angle, 2e, at the oxygen atom bonding sites.