Window glazing on sliding window nonmovable pane

Broken window on 1970s sliding window with no visible way to remove this window for easier repair. Gray glazing material is hard and will crack easily due to age. Only identifying label is AAMA quality certified architectural aluminum with code 122-1.pabe size approximately 16 x 46, so could get by with 2 6 foot lengths. Several other windows in the house have small cracks in the glazing, mostly at the latch location.