Diamond IR windows synthesized by low pressure activated vapor deposition techniques have been demonstrated by a number of organizations in recent times. Most of the optical properties of such windows have been shown to be identical to those of natural diamond. However for the practical utility of such windows the economics of manufacture have to be considerably improved. In particular the growth rates for large area windows have to be increased. Among the techniques being developed for the synthesis of diamond films and bulk diamond slabs the combustion flame synthesis process has some distinct advantages in terms of achieving high growth rates and low manufacturing costs attended by high quality. Using this approach optical quality diamond windows have been fabricated at growth rates of 5 to 10 microns per hour. This process also has the flexibility to control the microstructure of diamond to suppress columnar growth of diamond crystals and thus enhance mechanical properties. The current status of this technology is discussed in this paper including a presentation of the microstructural, optical, electrical properties and rain erosion data of combustion synthesized windows and coatings.