An Al-phosphate glass containing Nd
3+in concentrations ranging from

to

ions/cm
3has been prepared and investigated spectroscopically. Different ways of measuring the
4F
3/2→
4I
9/2emission cross sections yield values between

and

cm
2. At the highest concentration the decay time is 50 μs, while the radiative lifetime is estimated to be

s. Lasing experiments were performed by pumping thin platelets of glass coaxially with a dye laser. Cross sections, losses, and differential efficiencies are derived from these experiments. The status of high concentration glasses versus stoichiometric Nd compounds is reviewed.