Repeat changes from warm to cold and back repeatedly will tend to see the expansion and contraction on any material. Any existing weakenesses in the material are then amplified to an extent. Having worked in the tool + die plus cnc maching for a number of years you get to see problems with various types of materials worked with.
The type of material used in optical disks can harden up when seeing rapid temp changes causing warpage of the material itself where the stresses are brought out when spun at a high rate of speed as seen in drives. To see one fully disintegrate like that one did however is still a little rare.