The possibility of shell disintegration in thin‐wall targets as indicated by mixing of target surface material into the compressing core in laser‐induced implosions has been investigated. Aluminum coated glass microballoon targets were irradiated by a two‐beam Nd:phosphate glass laser with laser power up to 250 GW on target. The occurrence of mixing in these exploding pusher implosions was determined by using spatially resolved x‐ray spectroscopy. Mixing was not observed except for laser shots with an intentional prepulse (∼10 mJ, 1.5 nsec before the main pulse).