  We present a model atmosphere analysis of ten new DO white dwarfs and five
new PG 1159 stars discovered in the Sloan Digital Sky Survey DR1, DR2 and DR3.
This is a significant increase in the number of known DOs and PG 1159 stars. DO
white dwarfs are situated on the white dwarf cooling sequence from the upper
hot end Teff ~ 120 000 K down to the DB gap (Teff ~ 45 000 K). PG 1159 stars on
the other hand feature effective temperatures which exceed Teff = 65 000 K with
an upper limit of Teff = 200 000 K and are the proposed precursors of DO white
dwarfs. Improved statistics are necessary to investigate the evolutionary link
between these two types of stars. From optical SDSS spectra effective
temperatures, surface gravities and element abundances are determined by means
of non-LTE model atmospheres.
