Robert Edmiston was found guilty of assaulting his former colleague twice during a shift in August last year at the Braemount complex in Paisley.
But he will have to wait until next month to learn his fate after Sheriff Seith Ireland called for background reports on the first offender.
During the trial it emerged that Edmiston, of Paisley, struck twice, targeting the unsuspecting woman on August 26, 2013.
The 44-year-old had pleaded not guilty to sexually assaulting his co-worker.
Edmiston's victim relived her ordeal while giving evidence against him.
As he convicted Edmiston yesterday Sheriff Ireland said that "without doubt" he thought the woman involved "was telling the absolute truth about what happened".
He added: "Her evidence was convincing and she was emotional."