I have an R script that loops through and reads multiple Excel spreadsheets into R using the XLConnect package. The individual spreadsheets are combined into one large data frame, and then written out as a .csv file for further use in Excel.

```
newDf <- readWorksheetFromFile(filename,sheet=newid,header=TRUE,
                            startRow=1,endRow=17,startCol=1,endCol=6) 

```

The Excel files have one column of time values in a custom format: HH:MM:SS.000 

i.e. 00:18:06.264

When I open the resulting csv file, the values of this column appear as, for example, 

```
1899-12-31 00:06:18

```

While I can easily remove the date (which I don't want) after the fact, my issue is that the decimal levels of the seconds are lost. I need to keep them. What is the correct way for me to keep the custom time format intact?

Thank you.