The absorption and fluorescence of inorgan ic glasses and polycrystalline disks doped by heavy metal ions is discuss ed , and their use as fluoresce nce stand ard s is evaluated. The advantages of the glass standards over other media is summarized.The glass standards are divided into two groups (1) glasses doped by trivale nt rare earths such as Gd3 +, Tb3 +, Eu3 +, Sm3 +, and Tm3+ which have narrow band optical s pectra as a result of intraconfig~rational transitions, and (2) glasses and polycrystalline disks doped by ions s uch as Tl+, Pb 2 +, Ce 3 +, and Cu + whi ch have broad spectral bands since th e optical spectra originate from interconfigurationally allowed transitions. Optical and physical parameters , including matrix effects, quantum efficiencies, decay characteristics, Stokes' shifts and spin-orbit versus orbit-lattice interaction s due to the different trans itions wi ll be discussed.Group (1) glasses are suitable for use as standards where a narrow well-defined fluorescence range is required, and group (2) glasses are suitable for use as standards whenever a substance with a wide range of fluorescen ce is measured. Special em phasis will be placed on energy transfer between donor and acceptor ions.