The glass composites include glass frit, that when sintered produce a phosphor-containing layer, suitable for use in optical applications. The glass composites can include a crystallizing glass frit, such that phosphor crystals precipitate from the frit composite during sintering, or can include a non-crystallizing glass composition, such that phosphor is added to the frit composite before sintering. The sintering temperatures of the glass are relatively low so that fluorescence of the phosphors will not substantially degrade during sintering. The resulting phosphor-containing layer can be used in various optical applications including those for converting blue light into various color temperatures of white light.