Boron oxide with a content of 99.93 wt.% from the dehydration of boric acid was synthesized. Conversion of boric acid to boron oxide was completed within 3 days at low temperature range (T < 130 degrees C) and approximately 30 min at high temperature range (T > 130 degrees C) for the isothermal dehydration reaction in the temperature range of 80 and 350 degrees C. Apparent activation energies were 65 and 28 kJ.mol(-1) for low and high temperature ranges, respectively. Thermogravimetric analysis (TGA) results showed that the reactions were nearly completed at around 330 degrees C, and activation energy for the first temperature region was found to be two-thirds of the isothermal value and the same for the second temperature region. Isothermal data analysis revealed that the apparent reaction order value was around 1.0 at low temperature range and decreased to 0.55 with temperature within the high temperature range.